I have SE slip on's with the baffles removed and they are 3-1/8" round as you might know. They sound good, but have alot of popping at times and there is a bit of low end power loss, but not too bad. So I thought about useing the thumb screws as Lollie pop's as I have read about, but they do not make them very large so I made my own. I used L brackets like for a shelf (about 1-1/4 long on each side of the 90 drgee bend) Then bolted two 1 5/8" washer on each side of the L painted them flat black then used a Allen head screw and lock nut and washer the attach the other side of the L to the inside of the SE using the stock lower baffle hole.

So I noticed right away my idle is not as loud or deep so I took it for a ride. WOW! they do work. at about 2500 RPM the bike is alot more mellow, but gets loud when you get on it and there is more low end power at times, but I lost that awesome nasty back idle so I pulled them back out. They are super easy to take in and out so I will keep them if I take a long trip and want the bike not so loud. They cost me about $5 to make.