I also use FP4+ in 120...but still with contact printing in mind. I like its flexibility and Ilford's quality control and dependability.
FP4+ seems to build up greater highlights than HP5+ is capable of...which may not be as big of an issue with silver gelatin printing...some alt processes need the extra density range FP4+ can nicely expand to.
A few years ago when I started making salt prints (and later, Kallitypes) I was adamant that I remove all computer/printer technology from my workflow (no digital negatives for me, thank you very much), which meant making in-camera negatives for alt processes. I discovered
Ellie Young's document on Salt Printing which gave detailed instructions for producing in-camera negs precisely for this purpose. In it, Young demonstrates FP4's superior ability to be manipulated to work optimally for Salt and other "alt" processes, using PMK as the developer.
If suddenly everything else disappeared from the market, leaving only FP4 to work with, I could live with that. It's a very flexible, reliable and beautiful film.
I am so out of touch with silver gelatin printing. The long-ago loss of Agfa's Portriga Rapid turned me to the alternative side.
Ahhh - Portriga Rapid. What a magnificent paper that was. Vaughn, have you looked at Fomatone MG Classic? It has some similar qualities to Portriga Rapid, at least color-wise. Behaves differently, but it
can look a lot like the old Agfa paper.