The nice thing about Avons is that they stick right away, no break in necessary. I bought some Metzlers for the Daytona and went down coming out of the first corner on very gentle throttle application. I didn't mount the tire (190, too big) and hadn't noticed the coating of slimey form release all over it.
Avon must have an extra process which removes the slime. New Avons squeak like grippy running shoes on bare concrete, Metzlers do not. Wish I had noticed the difference before riding!
My Commando has 100/90/19s Roadriders on Flanged Morad WM3 s (Central Wheel) front and rear . The handling is wonderful.
As Nigel points out, wide rims are needed for small tires with the Roadriders. The WM3 is the minimum recommended width for the 100/90/19, WM4 is ideal according to the Avon chart. Central Wheel did not have WM4 in 19" at that time and did not know when they could supply them, so i went with WM3.
The WM3/ 100/90/19 Roadrider setup works down to lean angles where things are scraping, good enough!
Glen