Now that I have this '73 Custom with original T-Tops, I use the neck pick up on my Les Paul all the time for rhythm, especially on the IIB channel of my VII. It's a fantastic, Stones-y rhythm sound and can even get close to a Strat neck pickup vibe (scale differences aside).
I get it now, all those old guys complaining how modern LP neck pickups are too boomy, bassy, etc. This T-top neck is the sweetest, clearest, least bass-heavy LP pickup I've ever played, just love it, can't emphasize enough how much more clarity it has vs the Bare Knuckles in my R9, Gibson PAFs, and even Lollars I've had. The ebony fretboard probably helps, too, but overall these are the greatest LP pickups I've ever played, no exaggeration and I know I gush about them a lot, lol, sorry can't help it.
So yes, 70s T-Top neck + IIB is a great rhythm sound.