to be honest Inf is the unit I've been using all my time playing BD and it always gets me to the top 10s or 20s

another key thing is good allies, that is one key to victory...another is your mom's credit card...

anyway, I always go 9/0/21 when doing inf and I would also sometimes for the fun of it, include 2-3 squads of 60-90 damage units

anyway, when I spam, I always include 1/0/1 so you have a better chance of winning.

that's all!
Pblee

20 Range and 10 Armor is the best, try simulating it in the Battle Simulator.
No, use Tank Spam. I sometimes use damage spam, 5 Damage units for fun.

I like this guide, thats all there is to it