I've shoved the seat back as far as it would go. I order the B68, will have to check the packaging to make sure that is is. (The image isn't of a B68, I pulled down probably the 67 in order to have a top image similar to the 68 to use.)

The saddle is 168mm wide - the foam / specialized board measured out my sit bones at 140mm and my home trial came at 150 - so if I take the larger and divide that says I have 9mm between my sit bone & the edge of this saddle. I guess that might be the case based on where I feel like I'm hitting - I have felt back there and all I can find under my sit bones is the edge/rivet area.

/sigh - gonna *try* a group ride today, but feel I need to bring a spare saddle somehow.