An electric US? Sounds pretty good to me.
Put it on the ground, plug in the arming switch, and go fly!
The cowl air scoop idea for the ESC sounds good. And your idea about the slots in the cowling as well. What might look neat would be some fake exhaust headers in the slot, sort of like one might put on a P-51. Or you could do angled slots, like the cowl on a Beech Bonanza.
As Ser00 says, the plans call for a 1/32 gap between the cowl and the spinner. The way GP has you build the cowl that's probably achievable, but my gap ended up closer to 1/8-3/16's. You don't notice when it's 100 feet up!
I built mine as a tail dragger, the struts on my retracts are about 6 inches long, and I've got about 2" of ground clearance with a 13" prop when the fuselage is parallel to the ground. That's enough for a 14 inch prop (if I land and take off carefully!), but I think you'll have problems with a 16 inch prop unless you make the struts longer. One thought: don't the bigger electrics typically spin slower than glow engines? If that's the case, you mght consider a 3 blade prop that smaller in diameter to give you enough thrust.