The problem with prop clearance is not as bad as it first sounds. I fly a trike gear King Altair from a sometimes bumpy grass field, and have used 14 inch props without problem, and even a 15inch. The tips DO turn green, but there is no problem getting off the ground. A lot depends on the size wheels you use. I use 3inch wheels on the mains and 2.75 on the nosewheel.

The plane will fly slower and more constant speed witn the 4-stroke, and you should get better vertical performance.