RE: Webra .50 GT
My Webra 50 handles an APC 12.25x3.75 great. I have it on a Burrito profile. Some folks like the 12x4 or 11.5x4 better for 3D, but mine has done so well with the 12.25x3.75 that I have not bothered to experiment.
If posts in the Fun Fly forum are an accurate gauge, the Webra 50 and the Irvine 53 are the top dogs in the 2 stroke group for 40 size profiles.
Eric