Testbed

I usually use a mix of the top nano bots (because they let me run battles faster).

My usual test bed doesn't contain a single robot more than once. A diverse test bed seems to be better. If you really want to focus on a certain task, e.g. dodging HOT bullets, I can also recommend running battles in a 800x800 battlefield with 3 HOFs. This simulates the "middle game" where the weak bots are already dead and you have to fight to get into the 1vs1 stage.

My standard test bed looks like this: 1000x1000 HOF, DustBunny, Infinity, DoctorBob, Wallaby, KomoriNinja, Lib. This collection covers 80% of all melee movement and targeting styles. Sometimes I include SittingDroid to see whether I can fire at him fast enough. Sometimes adding a rammer is interesting too. I can also recommend testing a simple bed with nano and micro bots, and afterwards testing the same bed but replacing one of them by a top melee bot to see how your bot compares to that one.