what engine do you suggest?
I like 4 strokes myself... YS 63, Saito 82 would be MY only choices.
I think you'll be happy with any of the 50 something 2 strokes or 70 something 4 strokes... vertical will not be lacking.
I want to have unlimited vertical
Depends on YOUR idea of unlimited vertical... too some it means pointing the nose up and gaining altitude even if you have to fight the plane some what... others want the plane to accelerate as it's going straight up and out of site... yet others will want to be able to roll and do a few snaps on that up line... all require different amounts of power
John