Going through a similar experience with my BSR, except her complaint is that her "butt bones", not tailbone, seem to get all the pressure. So, I got the George Anderson TP relocator and put it in the 1 1/2" back position...2 1/2" seems too far back for someone 5'3" (my BSR) and seems that it would make her lean too far back, or not have her butt totally on the seat. The 1 1/2" position seems to have everything lined up perfectly, considering the lumbar support in the backrest. I also had the rear floorboards swapped to the opposite sides so that the adjustment was to the rear of the bike prior to installing the TP relocator, but since she's further back now, it appeared that her calves were going to contact the bag guards, so I moved them back to the proper sides and have them one notch forward of all the way up. Got her to sit on the bike, and it looks like her legs are level to very slightly down at the knee, which should distribute her weight evenly on the back of her thighs and butt, and she'll be able to change positions a bit by sliding forward or back, and stretching her legs forward, or pulling them back. Haven't been able to test the new adjustments yet (it's been too damn hot to ride here lately), but it APPEARS that this might work better.
Honestly, the jury is still out on whether I like the adjustable passenger floorboards...they get in my way big time when moved forward too much, and seem a bit of a stretch for the BSR as well, unless she has longer legs or is taller.
On my '06 SEUC, I had installed the Kury adjustable pegs and that seemed to work well for my then BSR (different person), who was about 5'4".
The new bikes with the Lumbar thing almost REQUIRE you to relocate the TP backwards to some extent, compared to my '06, unless you've got a really tiny BSR. My BSR is 5'3" and 120 lbs, so that's pretty tiny in my book, and she didn't have enough room between my backrest and hers. The Lumbar support is a nice feature, but it was not thought out all the way through, IMO. Not surprising, coming from HD...