Spark plug reading
Your rings are seated, they are pretty much seated by the time you have assembled/installed/adjusted the valves etc just by turning it over by hand. Unless you have a gas ported piston and even then, they are probably seated. You can wash the cylinder walls and glaze them after you get it running and it would appear as if they never “seated”. Most failure to seat ring issues are probably more of super fat after first start up and wash the cylinder walls and glaze the bores issue. Something I did a long time ago, was weld an O2 bund in the exhaust. Then buy a cheap 2 wire O2 sensor for an old Chevy truck for like $20. Connect the leads to a cheap digital volt meter. Now this is NOT very accurate! But it will get you in the ballpark. You can search online for what afr corresponds to what voltage. I found this online
Your rings are seated, they are pretty much seated by the time you have assembled/installed/adjusted the valves etc just by turning it over by hand. Unless you have a gas ported piston and even then, they are probably seated. You can wash the cylinder walls and glaze them after you get it running and it would appear as if they never “seated”. Most failure to seat ring issues are probably more of super fat after first start up and wash the cylinder walls and glaze the bores issue. Something I did a long time ago, was weld an O2 bund in the exhaust. Then buy a cheap 2 wire O2 sensor for an old Chevy truck for like $20. Connect the leads to a cheap digital volt meter. Now this is NOT very accurate! But it will get you in the ballpark. You can search online for what afr corresponds to what voltage. I found this online