Thanks for the offer Hein.
As they are, the straps work really well and are mega comfortable.
Not having pad up front of back strap is no problem.
My back foot is actually on the pad most of the time.
Back strap sits about an inch in front of middle fin. Could have put it back an inch, and put front insert on pad, but wasn't confident of my ability to cut square out of pad.
As it was, turned out to be simple. Used felt pen to mark outline of square, then cut around it with Stanley knife. Then used a chisel to get square off, and white spirit to get sticky stuff and residual pad off.
NSP board has a moulded inset to put pad on, so pad is less proud than usual, and you don't notice much of a step at front edge of pad. Couldn't get board without a pad.
Thinking of doing a 5' 10". Would probably cut two squares in back pad, putting back strap a bit further back. Would also consider using using surface mount footstrap inserts for front strap, without pad. Padz have more sticky stuff overall than inserts, and I imagine are more durable. So far inserts (and Padz) are brilliant.