I was thinking a 20x10 would work but maybe too much pitch. I was trying to determine prop size based on what 40cc to 45cc engines run and get a happy medium, but a 20x6 for break in and a 20x10 sounds good. I did get the firewall drilled out, cowl cut out to fit on the Christen Eagle. Hope there is nice weather next week, should have it all together to fly. Will post some pics of it tomorrow