RE: ***CUB BROTHERHOOD***
Ran my Sig 1/4 size clipped wing Cub with an O.S. 1.08FSR on both wheels and floats. Way, way more than enough power. Your DL 20 will be fine.
In fact, on floats, with full up elevator and instant full throttle, the O.S. would haul the plane right out of the water without a take off run. Next go around, I think I'll try an O.S. 1.60FX.
The 1.08 was the largest 2 stroke glow engine you could get at the time or I'd have put in something bigger since I was initially concerned about being underpowered.