[jspatz1]

Don't worry if the bottom thrust washer contacts the other bearing. It is a bearing, eliminating this friction is its job. (If you are still trying to picture how the thrust bearing works, it is a 3-piece sandwich...washer - rollercage - washer. They are not connected, just aligned together by the shaft.) You should however make sure the bottom thrust washer is relatively well supported, not just by its very inner or very outer edge. If in doubt, add a another plain washer between the bearings.

A tapped setscrew hole is very easily added to any hub or coupling you encounter that needs one. A tap at the hardware store is < $5, and you'll have it for next time. If you need a lesson on tapped holes, we could do that.