Apparently Sanderson started partaking when he was 19 years old
H: well, for wt believers that means being part of the "bride", feelings that in a different way are powerful at the period in life.
He is cooperating with D. Splane, who, in that "timing chart" talk, in so many words said, that 2 centenarians overlapping by ~ 20 years like Frederik Frannz and now M. Sanderson,* would bring the overlap generation to 2075. 1914 + 2x (100-19) = ~2075.
* assuming that M.S. just as the example cited, was 19 in 19192, and lived past 100.