Thanks to all for your input.
My hobbyshop guys say they use the 30-3P, but have no experience with the 40-3P.
I will take your advice and pay the little bit extra for the upgrade. Because they will be testing my model, I'll report back on whether or not they think it was worth it (I'll bet it is). Of course it may be quite a while before I actually finish the thing!
Thanks again.