Thats fine 10 minutes after it was started but where was it at 20 hours at 40 hours?
About 98%, actually. When I did his top end, I also ran a leak down test on the assembled engine before it was run, just to collect some info. At that point, rings straight out of the box, it sealed 93%. After cycling the engine through 20 revolutions with a wrench on the crank, it tested at 95%, with the oil as described above.
The point of dry building rings is supposed to be that the compression rings have to be seated to seal at very high efficiency before they develop a coating of combustion blow by deposits that will prevent them from sealing correctly. The only influence this will have on longevity is that if the rings seal quickly, they will seal for a long time because the lack of leakage will reduce the contaminants that might otherwise be deposited over time and reduce their efficiency. The fact is that modern piston rings fit to a properly finished round bore seal almost immediately regardless of how they are assembled, and for more than 99% of people, there simply is way too much made of the whole process beyond the question of bore condition. There may be some advantage for racing engines where the ability to extract every tenth of a horsepower
possible, but in my experience, there's no provable benefit to dry building in terms of longevity, and no performance advantage in the vast majority of cases.
Even if the rings are built dry, cylinder will stay dry on start up for what, 40 or 50 revolutions? If you really think the rings need that much time dry, you can dead spin it before starting it without running the risk of scuffing the piston skirt. In the case of a two-stroke the question is even sillier, since if the engine fires, it has oil on the rings because it comes with the fuel anyway, so again, why bother, and why take the risk? (BTW, the fuel; is the primary compression ring lubricant in a 4T as well)
As for other reputable builders, more than you think are using dry moly lubes on the rings. Technically, this means they are dry, yes, but they aren't being run without lubricant, and the only thing being avoided is actual oil on the ring faces. Ron Hamp (the first builder I'm aware of who legitimately got 60+ hp from a 5 valve YZ450) does it that way.
The whole myth about synthetic oils during break in is based on the entirely false beliefs that too much lubrication will prevent moving parts from wearing into each other correctly, and that synthetic oils are somehow "slipperier" than petroleum oils. The function of lube oil is to prevent ANY metal-to-metal contact of mating parts from occurring, and precisely because the surfaces of new parts have not worn to a matching finish with each other, the integrity of the lubrication provided during this time is actually more important than it is later on when things have achieved a nice polish. Synthetics in general are simply more able to maintain that integrity under a greater number of adverse conditions for a longer period. The only downside to using synthetics for break in is the expense of discarding the used oil at an unusually short interval.
As far as disparaging the vehicles mentioned as "passenger cars", Corvettes, Camaros SS and Z28 models, MB's, and Porsches, among others that fall into the group built with, shipped with, and required to run synthetics are hardly in the category of an Olds station wagon from the '70's. In fact, now that the norm has become asking a 3 liter engine to do the work of a 5.7L at 50 degrees higher operating temperatures, and do so for at least 200,000 miles, it would seem the longevity question applies much more to these vehicles than to an off-road motorcycle.
In any case, I build my stuff as I described, and I will continue to do so because it works, and works with a success rate as near 100% as can be imagined. Anyone who wants to is free to go about it any other way they choose.