I am at the point of completing a large plane for use as a camera-video plane. It is an original design with the following specs:

Span 134"
Chord 18"
Airfoil NACA 6409 modified
Airframe weight without engine and camera equipment 13lb 4oz
Configuration Twin boom pusher.
Design stall speed @ 21 lbs 22 mph
Expected operation speed 25 to 35 mph

I would like to use a 26cc Shindawa that I have since it is the lightest engine. However I have a 30cc Kioritz, 32cc Mac, 35cc Stihl and a 38cc Echo.

All have operated on gas/glow mix and perform well.

Any thoughts on which engine would be best?