Congrats on the successful maiden !!
There's nothing quite like the feeling of getting your pride and joy back in one piece after its' first flight, is there
I generally use 2650mAh batteries on my 70mm jets to get decent flight times, and now that I know, 30C is the lowest rating that I will use. It keeps the heat down as you're not working the pack to its' maximum all the time.
Not sure about the smaller one, but on my 90mm the nose-gear opening let lots of cooling air in for the battery, but I had to make a couple of openings to let the warm air out into the ducting in front of the fan. It seemed to keep the battery a bit cooler.