I too have never heard of anyone having a problem with Keith's plate feedway profile. The condition I was trying to describe is not a problem per se in that it is not a functional problem - better described as a cosmetic anomaly in that it doesn't follow the feedway profile of the 1919a4 really well. Of the three best manufacturers, Keith's is the only one that I've seen this on - does it matter, not really except to those that are as anal as I am. Here's the only photo I could find to better describe the condition
I've only heard really good things about Keith's plates. His plates are excellent.
As far as heat treating, I'd agree that it is probably not required for SA operations although it is recommended if you add a handcrank. Once you've welded your sideplate for compliance, it becomes more difficult to ever swap a sideplate out if you later need or choose to.
I'd wholeheartly recommend any of these three manufacturers of sideplates.
"I don't want to push anyone one way or another because as you can see there are more than enough good options to go with. Just enjoy your build and the end result." -------Shortrnd, I'll second that !!
Another thing I think we all can agree on is that you can't go wrong with any Weaponeer group buy - some of the best deals and highest quality around.
Top photo is Keith's plate. Bottom photo is Todd's plate