Thanks for the review. I have been running Primo Comet kevlars on my trike for several years, typically getting about 3k miles out of them, but this summer the price of the kevlars skyrocketed and put them pretty much out of reach. I was thinking of trying the Scorcher but hadn't because they would be hard to obtain.
 
I'd recommend against running mr tuffys anymore. A couple of years ago they changed the compound or the substrate, I forgot which, and they went downhill. They used to last a long time out of the tire if not in sunlight but now they crack in short time regardless of how they are stored, even in a tire. I finally took the last one out when I had a blowout just after hitting 50mph downhill not long ago. Looking at what was left, it was pretty clear the liner had cut through the tire sidewall and caused the blowout.
 
I'm running non-kevlar Comets for now. Don't like the alternatives but not sure what to use. The Comets worked good on a trike because they didn't stick too well which is handy on a trike. Not as good on a bike though. :^)
 
I've been putting 406 Conti Contacts on the LWB ebikes. Good traction, low pressure though they still have pretty decent rolling resistance, and excellent wear. I have the Conti here that my daughter put over 4k miles on and you would have trouble distinguishing it from a Conti with maybe 100 miles on it. Almost no tread wear. And this tire is mounted on a hub motor wheel, so one might think it would have a lot more wear. None of the Contacts I've mounted on ebikes have had a flat yet, and that's over 10k miles in the year since I started using them.
 
Have you tried the Conti GP 406s? A bit expensive but I think I'll try them on the trike next.

Ok. I can see that. I don't know if it would be worthwhile trying a 20x1.75 Conti Contact or not. They are a pretty inexpensive tire so maybe not out too much if it doesn't work. I run 16x1.95 Maxxis Hookworms on my pushers. They have been a very good tire for that application but more tread than I like for non-assisted tires. Might work in your situation. I also run 36-spoke double-walled rims with them for extra strength. I know so many people like Schwalbe's but I haven't had good experiences with them.