I guess am the odd man out on this discussion because I always found the LA40 to be a fine engine, perhaps better than the LA46 for the run style I like in a small classic size plane. The LA46 were a hair more powerful but do you need it for a Fox35 size ship with a thin airfoil? The 40 didn't need as much diameter, which for me, was more important when putting in the typical classic bird like a Nobler where a 12.25" prop isn't optimal. The LA40 with a 10.5 to 11" prop sounds like a winner to me, and if using the APC fiberglass optimal 12 3/4x 4 3/4 LA46 prop, the smaller diameter LA40 prop, especially in wood like a Topflight PP 11/4 just saved you some tail weight you might be worried about with the LA46 and larger prop, not to mention that weight is further forward and creating less procession.
EricV