Please note: I am by no means a qualified expert, so take this with a pinch of salt
It is my understanding that, because Dyform has less stretch than standard 316, it's advantage is in performance. Essentially, using Dyform will make your rig stiffer, so that you will get less deflection in the mast
under load (from wind
in your sails). Essentially, if your mast
remains stiff, your sails
remain in their design shape..if your mast deflects, your sail distorts and does not perform as designed (or so your sail-maker will tell you)
I suspect that the difference is not significant enough that you would actually notice the improvement in performance between standard 316 & Dyform (assuming both were well "tuned").
If you are trying to get every last iota
of performance out of your boat, and are looking for another 0.1 knots of speed, so that you can win your local championships, but you have already bought a brand new set of D4 sails
and replaced everything you can with carbon fibre, you might want to consider using Dyform... otherwise, just stick with standard 316.
But like I said, I'm just shooting the breeze.