150 is not that much... But, most people who intend to run 150 end up with more.

NO WAY IN HADEES I would run that gap on a second ring. But, that said I do not follow the flock with the larger ring gap on the second ring. The idea is whatever gets below the top ring should have extra room to get by the second. Ring flutter comes from pressure between the rings. Keep it up and eventually you put so much pressure between them with a little heat in the valve pocket and you lift the land. The top ring will always see more heat than the second. Which equals more ring expansion in the top ring. I set my gaps the same but, ran fairly large gaps.

Leon