The type of honey used has little effect on the final product . It's the seed added that directs the size of the crystals formed and the physical rubbing that determines the final smoothness. I should also add.....as is the temperature it's made at. I cannot make good soft set honey in warm summer weather regardless of source of honey
However, it is a very good idea to make soft set using honey that normally sets really quickly and cannot be sold as "runny", like OSR which sets really quickly and hard with a fine grained crystal. This was my main "go to" for soft set honey until they stopped growing it around me. Now I make it with anything to hand.
Interesting, like yourself Mick, I find it a poor seller in Middlesbrough, but on some markets it outsells runny. About a 1/4 of my sales are soft set honey.