Re reading this. I have not used studs yet for flange, I am using bolts and the PO has lock washers with gaps on both bolts. Interestingly, before the winter break, on last engine run after new hot section install, I had been troubleshooting wispy exhaust leak(tough to isolate) that is near the starboard side flange bolt head. I now wonder if the lock washer is one of the problems. I have tightened bolts and hot section assembly, did not run after adjustments. This is what it looked like before winterized. Best viewed high def at .25 speed. :12 best freeze point.
https://photos.app.goo.gl/Fe51MqVN7p7DgJSw7
p.s.
I also had a slight water droplet above the injection point. Was able to adjust both the nipple going into the flange, and the nipple going into the injection point- will be testing as soon as I de-winterize engine.