A 200 A fuse is what I chose after blowing a couple of 80A ones, Its based on being less than the maximum current spike the batteries are rated for but more than the weapon ESC. For that battery in the photo, the fuse should be lower than the 165A peak the pack is rated for.

That pack is rated to supply 82.5A continuously and 165A for short periods (usually around 10 seconds). Most packs will get quite hot when running near their continuous rating and my guess is that your set-up will be pushing the pack hard if you powered everything from it. I would look at using around a 4AH pack rated for 65 - 130A to be sure you have enough current capacity for all the motors.

BTW: where did that hilarious pulley quote come from? I'd definitely take up Harry's offer.