I've been wood carving for about 15 years or so. "Carving sharp" is superior to "shaving sharp."
I make strops out of leather, denim from old blue jeans and just about any card stock inside faces from cereal and crisp boxes.
Doesn't matter very much, as long as it's quite smooth.
I can't comment on Autosol. Never used it. But also, never read a negative comment about it's performance, either.
All along, I've used Chromium Oxide (green). . . CrOx. Here, it's usually laced with Aluminum Oxide (AlOx) which is white, it disappears in the CrOx except for the lumps
when they don't mix it well! No big deal. I have straight white AlOx on denim strops.
I scribble the CrOx on the card stock strops and when they are all black, I start over with a new one.
3" x 5" filing cards wrapped around mandrels are good for all my Pacific Northwest style crooked carving knives.
On leather, I use the serrated corner of a small mill file to gently rake off the blackened CrOx and recharge the strop.
How often depends on how much use it gets. I need to see the black trail of metal particles to understand the effect I'm getting.
I don't like leather as it goes soft over time. It rebounds at the passing edge of a tool and rounds off the bevels.
Crappy cheap box card stock is superior.