On my other bikes, I use Selle Italia Max Flight saddles; the Sojourn came with a B-17. I followed the directions on using Proofide to the T.
Lo and behold, when I wear my Aerotech bibs, I get a nasty abrasion in the perineal area. I know the the Brooks takes time to break in and this doesn't happen on the Max Flight saddles which has a huge relief cut-out. I wasn't sure if this was a need for the leather to soften around the 3 holes in the center of the B-17 or what.
Is this the result of the B-17 not being broken in yet or is it due to the seam running down the center of the shorts, under the chamois? I do not have an sit bone pain from, thigh rubbing etc. I have half a mind to swap saddles since I know the Selle Italia works for me and started to experiment with shorts could get expensive...
I have experience with problem.
You say, "when I wear my Aerotech bibs"; change bibs.
If abrasion is more on one side, try slightly offsetting saddle.
Try slight offset from horizontal.
Use ointment, such as Bag Balm. Use hydrocortisone; available without prescription.
Swap for B-17 Narrow.
Have you toured with the Selle Italia? May feel different after many days.