RE: Battery headache
It's very hard to find batteries from the Chinese marques with deans on them. Don't worry at all about the plugs, just get yourself a soldering iron, it's dead easy. There are loads of vids on youtube (how to solder deans) and just get used to changing the plugs on batteries you buy, we all have to do it...
Now that that's out of the way, battery specs... Your 30Cs should be ok for club racing, but higher C is always better. You'll know if your batts are under spec, if after a full 8-9 minute practice they are hot, then you would benefit from higher C.