Welp, I got my new modified spacer and bearing in last week (thx Armen!) and got them installed over the weekend (thx for the write up Dragbikemike!).
Took me about 3-4 hours total. Mainly, the heat/cool part and then adjusting the belt in the pulley since I don't have much wiggle room with the larger front pulley mod.

I never did any proper measurements of the pulley deflection other than grabbing front to back on the pulley and feeling a fair amount of play but it's been that way for quite some time (25k mileage). I always figured it was play in the rubber dampers that was causing it.
I have the modified front pulley too for those of you who are interested. I was a bit concerned that might be a problem but it wasn't really.

I've only had a chance to take it out on a couple of short runs after the install but holy heck, what a difference!

Absolutely no wobble now. One thing I didn't expect was that for the longest time, whenever I would lay the bike over in some steep turns it always felt a little sloppy coming out of the turns.
I figured it was just my imagination but with the positive contact on the pulley now I realize it was probably just pulley wobble...it is actually quite a different more confident feel.

If you're considering this mod I highly recommend it if the back end of your bike feels a little squirrelly.

Interesting!  I have had occasions on long sweeping high-speed corners where it felt like I was about to enter the Harley death wobble statistics book. I have always had the shim mod in my pulley, but wonder if those episodes were a result of the remaining pulley wobble?

Now that I have completed the swap I will have to pay closer attention to this next time I am out tearing up the empty town roads  

Based on the way I cut the grass, I may need you to make me some some of these spacers for my riding mower too  

Yah, I've put some miles on it...sorry, I haven't been on in a bit...being in Denver we go from snow to 70 degrees in the span of a few hours so spring riding can be a challenge...

Anyway, I took the bike out last Sunday for about a 60 mile ride. It definitely is an big improvement with the solid pulley working with me now. I had a stretch of about 20 miles with pavement grinding going on...I hate when they do that but the end result's are worth it.
Some sweeping turns and long straightaways made me feel like the back end was finally gripping when it should.

It's interesting to me that I always presumed the rear of the bike was always going to be somewhat sloppy feeling...maybe it's just my imagination but for whatever reason it feels nice and solid now.

Thanks again Armen and I'll get the core in the mail this week for you!

OK, so I got the last stock spacer back in the mail today. I have a few ready to ship if anyone is interested.
thanks!
-Armen

PM sent!
thanks!

Armen wrote on 06/06/20 at 09:39:07:


@Armen,

I could have been my mistake. That was my first time using the "gift" option in PayPal and their instructions did not match the onscreen options. I'll get the missing amount to you.

Copy on the bearing. I've ordered the ebay doublewide.

-JD