[ProfessorM]

Looking at your pics it seems that he used no wgt in the large one and only cupped the lip on the small one. The lip is mounted higher on the smaller one and looks to be on center on the larger one. His belly wgt also looks to be in the middle of the plug, Musso's was off center toward the back.

Looks like there was some tweeking done by BM to fit what he wanted it to do and I think his Jr. is basically a Musso Sr. clone tweeked and the larger one is a creation all to itself designed by BM wanting a larger plug. Hey smart move take a proven great plug and size it up to fit your need.

I found a few more pics I had. If you look at the far left there is a larger slopeheaded plug Musso made. It was a troller I believe. It is larger than his Sr.'s. Maybe BM copied that plug to make his Sr. plug. I do not have any info on that plug for some reason, even though I had it in my possession.