For posterity, I've also tried the FS7 bridge with a small ceramic. The sound is actually *very* similar to a Custom SH-5. So much so, that I went ahead and got an actual Custom to compare it against. The Custom has a little more "oomph," and chunk, at the expense of some tightness, but not by much.
The main difference is on the wound strings where the FS is tighter, but also a bit more anemic when distorted.
Also, my copies of both FS bridge and SH-5 Custom have slightly offset coils. By about 0.3k ohms. Might be within tolerance, but I remember the 6 string versions reading nearly identical for both coils. So does the Pegasus 7. I wonder if the 7 string versions of the Custom wind have offset coils by design?