I don't think I've ever heard of a rear bearing making a "thump" noise. A grinding or squealing noise, yes. I'm not saying it can't, just that its more likely its your belt or front glides.

Is the dryer level? Could something be in the tumbling arms?

And I usually found them with at least one washer on the back and then the "C" clip. I liked to put on a fiber washer then a metal one.

For some reason your link doesn't go anywhere for me.

I'd just put it on and try it. I had one once that I ended up putting about four washers on it just to get the drum where I thought it ran better.