I'm not concerned with the properties of either oil, as long as there is enough ZDDP and the oil meets the recommended requirements for viscosity and service conditions, it is beyond doubt for me based upon the number of HD engines I have rebuilt that any modern oil is going to be OK. These engines are unbelievably tough and the only failures I have ever seen from inadequate lubrication are either not enough ZDDP, the wrong viscosity in a big way, or a broken oil pump drive gear key.
Maybe I should have been more specific in my question -- I have read many cautions here about potential unexpected results from mixing different brands with different additive packages.
I have had great results from the M1 V-Twin formulation, there is a reason why S&S recommends it. I have also read some pretty unflattering comments here about Lucas, and while I have no direct experience or knowledge of it, I do respect the educated and informed opinions of many of the folks who post here so I thought it couldn't hurt to ask.