Re: I would like some feed back from those who have used Beemer Boneyard 10W-50 synthetic
Which part of the weight concerns you? The 10 or the 50? Neither concerns me, as I use a 5-50. Some will argue that 5 is too light, but remember that viscosity will change even in ambient temperatures. In other words, on a 90 degree day, it's more than a 5 weight. And I do tend to like the lighter starting weight on startup. I know it's getting through the engine quickly. Although I don't know the specifics of this particular oil, it sounds like they're using moly, which offers a great boundary lubricant. That boundary lubricant is what you're depending on at cold start and heavy shock loading - like hammering the throttle.
Of more concern is the manner in which the oil mfg. obtains the weight difference. Usually it's through polymers, which can shear out after time. Only oil analysis can determine the amount of shearing, and the time dictated between changes.
Also of concern should be the film thickness and strength. Even a light oil with superior film strength will out perform a heavier oil with an inferior film.
Last, the 50? General rule of thumb, heavier is always better until you lose lubrication. Fifty should be fine.
Bet THAT cleared it up for ya, huh?