Just a thought? Maybe finish out the season on the YS. By time next season rolls around the new rear exhaust DLE 20 should be out (VV says they're on the way). They HAD to have played with the transfer ports to do that (turn the cylinder 90 degrees), giving them a chance to "modernize" a little maybe? That new RE engine could very well have a little more poop - to put it in a pretty good position to compete with your YS 1 to 1.

Another thought. You might want to check out the new beam mounted RCGF 26cc engine. It's a little heavier than the DLE 20, but has the same foot print, and the extra cc's should give it significantly more punch. 18" props easily....