What is the best battery setup for a CRT?

I'm reconfiguring my Jammin CRT Truggy. I have the MMM v2 and a 1515 1700kv Neu motor and I'm currently running two max amps 4s 5000 mah packs in parallel. Which sometimes isn't so great because if you get a dirty connection at one of the deans it will only feed off one battery which equals an overheated pack.

I would like to go to a single battery setup, but I want to go with a setup that will be very cool running because it is very hot here. Sometimes I will check my motor temp before even running it and it will be over 100*F.

I'm kind of thinking about going with a 5s or 6s quality pack. I kind of like the Poly RC 6s 25c 6000, but that is a large pack. Would it be too heavy on one side? I not currently racing it, but I do run it on a track. What do you guys recommend for a cool running single battery setup on a CRT?