1. some small puffing is usually ok, but without touching it, hard to tell, maybe pics would help

2. I prefer to charge at a very low rate if I have to recharge to attain 7.4-7.6V, you can charge them at a higher rate if you like for storage, just try to be in the 7.4-7.6V area, even 7.8 is probably OK

Question: How low is your battery voltage when you begin charging? Usually I have to discharge batteries to get to storage voltage. I am a believer that running lipos in the car below storage voltage is a cause of puffing. That's a long discussion, but it may be that you are puffing lipos due to high current load at low voltage.