Re ring or not
The simplest way to trace a problem when doing a leakdown test is with your ear! 12% is way too much for a race application and when doing each cyl. always listen for blowby at three locations. The intake port, the exhaust port, and the crankcase. Once you start comparing sounds from good cylinders to bad you will know where your problems are. Intake noise, probably needs some valve or seat work. Same with noisy exhaust. Noisy crankase means ring problems. Of course I am assuming the engine is on a stand to make this fairly simple. Phil D.