There are different guidelines from different manufacturers as you've seen. You are probably going to get many other views also. Ringed engines should be broken in as you state. Lapped engines are varied! Saito guidelines are the only one I follow when breaking in a Saito otherwise I fill up the tank and run it rich @ about 3,500-4,000 rpm and just let it run. Then let it completely cool and run another tank. 3 tanks and you can then lean out the low for a reliable idle and the hi to a slightly rich setting and go fly. YS's I set on the second tank and go fly! Hope this helps.