Well, Lance, you're going to have some mistakes. That's just part of it.
My number 1 suggestion to anyone is take a few scraps along the way through the entire project. Watch straps aren't going to be using much material to begin with.
So, cut yourself 2 of everything. They don't have to be the same shape, just something to try out every step along the way. If they are the same make sure to mark the testers.
Chrome tan/multi tan is not going to be easy to burnish. I can only say each piece or side is going to take a little different technique.
The chrome tanned and unidentified leathers I have played with just haven't done too well.
This is the best chrome tanned burnish I have achieved.
It looks a little better in person, but not like a piece of veg tan.
I haven't played with the exotics but I imagine most of them will be chrome tanned.
And on another note, even the best veg tan is difficult to burnish when it is so thin as a watch band.
I suggest edge coating these bands if yours and saving yourself some headaches. But, I have only just recently delved into edge coating, so I have little to offer.
Tandy has a lot of their fenice edge dressing on clearance right now. I bought three colors in 32 oz. Bottles for 8 bucks a piece.
Good luck.