For what it's worth, I had a friend who had the Yellow Aircraft Spitfire and his was powered by a MOki 1.80.  It flew very well. I have a Yellow Aircraft P-47 , 82 inch span and around 25 lbs. I have a Moki 2.1 in it, and it also flies very well. Plenty fast enough for me and it will loop from level flight. 

What you have should fly it well, and should be easier to keep cowled in.

Dash