Zzyzxx,

General rule of thumb on selecting an engine for most planes the manufacturer provides a range of engine sizes select one at the upper end of the range (you can allways throtle back but full throtle is allways full trotle)

I've never owned a tower engine so I won't comment on it. The engine forum has had threads on this engine I suggest you do a search.

I have a GP .40 sized P-51 that i'm planning on using a SF .46 on. The one problem with detailing the smaller warbirds is that you can make them heavy which increase wing loading and makes them land hotter. So be carefull if you decide to "detail" you could in fact be creating a static model instead of a flying model.