^^Those are exactly what I've been running on my track bike for three seasons now. The track being Northeast Velodrome in N.H. Outdoors and asphalt, we go over it with a blower about once a week, so the track is about as clean as it can be. Off track, it's not, and I've picked small shards of glass out of the rubber more than once, but no harm to the tubes. No sealant ever, can't stand the stuff. Tread is holding up well but of course it hasn't been more than a few hundred miles.

I run them at 110psi or more and they're not cushy...

Edited to add: You're right to pre-stretch them and they will still be tough to get on. I kept mine on old tubular wheels for weeks and it was a fight even so.