Much depends upon where the CG ends up. On most warbirds I would say don't worry about the weight up front as you will most likely need it there anyway. However, the P-40 is one of those that has a long enough nose that you may or may not need a bunch of weight up front in order to achieve the proper CG. I would do some preliminary testing to try and find out if the G20 will make the airplane extremely nose heavy or not. If not then the 20cc would be a fine choice for a 62" P-40. I have two 64" span Hellcats, one with a DLE 20 and one with an Evolution 20, and while they have plenty of power it is certainly not too much by any means. One is about 11 pounds and the other is about 11 3/4 pounds RTF. Both required nose weight so a lighter engine would have been a moot point. My .02 cents.