Finally did it today. After installing the Dyna muffler my lean hesitation was exagerated and more backfiring. So today I dove into the carb. Honestly, the first time I have really did anything with a motorcycle, other than the muffler. And I was able to do it without removing the carb. No baby steps here, dove right in and modded it. Stock in my '07 was the 145 main. I installed the 150 I got from lancers kit. Also installed the pilot that was included, I have NO idea which one it is.
Installed it anyway. lol I than moved onto the spacer. After fighting with those two tiny philips screws and just about ready to not do it, the last screw gave way. NON of these screws on this carb have wanted to co-operate. Some may remember my mixture screw ordeal. I pretty much stripped out all four screws on the top cover of the carb. One of the bowl screws, and both of the spacer needle cover screws. A trip to Lowes solved the screw issue.
I had to actually drill one of the screws for the spacer.... I have a variety of Snap-on and Craftsman screwdrivers, they are not cheapies.
Anyway. The results. It still pops when I roll off to shift, very, very slight. And still the occasional fart/puff when I turn it off. No more low speed hesitation and she definately has some more go!
I adjusted the mixture screw, should have done that before I started it, got some black smoke on initial start.
It is set to about 1 full turn out. IMO, it's to a point where it could be left, or install an aftermarket air filter without any issues. I am very pleased and worth the time and aggravation.
Now I need to find the time to actually put some miles on it and feel the results a bit better.
A huge thank you to everyone here and Lancer.