Thanks to Remmy1187 I have made some changes to my trusty 870 SM.
I just installed the thumbhole and will try the JH .660 he sold me. Being new I didn't see a feedback section but Remmy is a great seller. I would do business with him anytime.
The comb was still a bit low for the b-square mount/Burris SpeedDot 135 so I used a stock raising kit I had laying around. I can't wait to pattern the JH and see how the stock feels.