I liked the AC/5 on the Urbie R63 variant due to the ballistics cooldown buff (15%) but the quirks on this Panther chassis kick it up an additional 10%. When adding a cooldown module, the AC/5 goes down to a 1.1 second cycle time (down from 1.66) which turns out to be fairly nasty - at least against targets you can hit consistently. Any engine slower than a 225 makes you way too slow, especially before speed tweak comes into play, so I think that something in the 225-235 range is a good sweet spot for having enough ammo to last through a long game. I'd recommend at least 3T of AC/5 ammo, 1T of SRM ammo, and possibly an extra half of whichever you tend to run out of first. The lack of lasers here is a big drawback when trying to fight light mechs but, hey, you do get jump jets.
My version, bit less armor/JJ but otherwise faster and more ammo. Even then ammo seems to be a problem sometimes, just saying.