Is there a recipe for the perfect shieldball?

No, it depends on your opposition. However, because most shield fac units are fairly cheap for their class, you can and should fine tune your composition on the fly to meet the evolving threats you'll face.

If they're heavy and so not particularly numerous, for instance tank, but also jump since jacks and juggles can really ruin an unprepared shieldball fast, you want to stack a good number of racketeers. Racketeers can also thin out incoming fire from a recluse ball that shield can otherwise only answer with cloaked snitches (bandits get chewed up fast because they're slow and have a fairly large hitbox for a raider that a recluse ball won't have any trouble thinning out on approach regardless of terrain) and they're good for bypassing crabs, spired or otherwise.

If you're likely to face large numbers of light units, you'll lean more on felons. Felons are also probably the best flex AA in the game.

You'll want rogues against porc, since closed Razors will deplete felon and linked aspis shields quickly for not much gain.

Your core meatshield is thugs and outlaws. Thuglaw by itself can be an effective means of pushing cheaply, but only if you're not walking into the teeth of massed skirmishers or artillery.

You'll see pure and almost pure felonballs in lobsterpots, but I believe they are generally overrated. Anything with adequate range and mobility (even badgers) will wear them down and force a retreat. An opposing shield player with time to acquire an iris will also have good opportunities to blow them away in one go with snitches.

The main shieldball specific threats you face are snitches and Likhos. Thunderbirds look scary, but with enough Felons (3 or 4 will likely be enough, 2 may suffice), they turn into a modest metal donation. Except in prohibitive numbers, outlaws will not by themselves deter an experienced snitch bomber, but they will make it more difficult to safely approach your ball. In essence, they buy time for mistakes to be made or for screening units to find the threat. If you can't count on your allies to do it, you at least have the dirtbag to call on, and if you've been investing in AA, Vandals can also fill this function in a pinch. Don't build them for screening purposes, but if you don't have dirtbags to hand and you need to screen your ball from bombs, they can step into the breach being cheap and probably numerous due to feeble individual DPS. Vandals are your only real active defence against Likho (besides effective allied air cover) and they're not great for it. I find the Likho usually gets through and gets to go home again, though it may fall prey to massed Felons if you're lucky.

In an ideal world, you don't need Aspis. They cost energy to charge and they're fragile. However, in reality, anyone with AOE options or lances will force you to invest. Scale number of aspis according to the size of those threats. They're also a passive defence against Likhos. While air might try to manually fire under the aspis, doing so is likely to require entering Felon kill range (or they might get hobbled by a lucky Racketeer).

Since shield doesn't have a true artillery option, you will suffer generally if you try to march into artillery (or massed nimbus). Don't do that.

Are those damage numbers a default widget?

What's the name of that widget?

Cloaked burst damage (like cloaked snitches) or about three thunder birds will make mincemeat out of your shield ball for a comparatively low cost. There will never be a perfect shieldball.

Shield balls have two base strategy - with felon or without felon. Each of them gives cons and pros.

->Felon ball pros - great damage burst which can destroy even powerful heavy units and even striders very quickly, can even kill approaching air units like Thunderbird or likho in few moments. Also destroy close range gunships, felon acts also as powerful riot so not always you need outlaw in your ball to defend against raiders. Felon ball can consist even only from felons and convicts or just only from felon because felon also have its own shields. Felon ball have 100% accuracy and instant hit.
->Felon ball cons - felon uses shields to fire and it deplete them pretty fast so then it becomes very vulnerable to arty units, likho bombers, phoenix, firewalkers and other units with aoe attach from range. Felon ball is less durable then thuglaw. If there is no racketeers/area shields then smaller felon ball is bad vs heavy laser turret spam which outrange them and before they get closer shield is depleted. Also as felon tends fire on closest target then it can waste much damage attacking nearby closer razor. One sniper can kill your fellon and then your balls looses most powerful damage source.

->Thuglaw ball pros - great meat shield which can storm most defenses on their own because they don't use their shields to made damage so shields are not depleted. Thuglaw ball is cheaper one because felon is not cheap unit. As thuglaw ball doesn't center at felon units like lances/snipers can't disable it with killing one central unit.
->Thuglaw ball cons - its slow and need get enemy closer then felons to deal with them. You always need thug and outlaw together because outlaw have low damage and only have slow while thug alone is weak vs raiders. Thuglaw ball also suffers more from air raids then felon ball because felon can attack air. Thuglaw is more bad against heavy units like striders until they gets racketeer in balls.


To defend against air you have three option - felon, vandal, racketeer. Felon in close destroys any air in few secs. Vandal is very cheap but with low burst damage so you nedd great masses. Racketeer can disable tb raids and also disable likho but they need to be manually microed to do it. But if u manage to do it properly then they become very good and every air player will curse you.
Against snitches/imps there is outlaw and also dirtbag screen can be made. Felon also deals with snitch throw.
Getting racketeer in ball is very good strategy. They can disarm even most strongest striders. Even detris in masses. Also they disable defense towers.
Area shield allow some strtegy to be used and they also offer protection against likho shoots if air player dont want to risk and dive under shield. As area shield blocks damage then you can get closer long range building and disarm them safely with racketeer. However needs remember that area shield uses energy to recharge so this mean you may become short of it.