I use the standard leather whether it is on my Schulz, Miller, Robertson or my own.
You certainly could use seal skin, but the original type rest is more than adequate. Due to the paradox the arrow bends inward on release and then around the handle. It uses the rest for a split second, the whole arrow does not ride on the rest upon release. The paradox is more pronounced with a longbows than a recurve, because the recurve is more likely cut past center(generally). Your form, release and set up are a factor as well, but it is primarily due to the design. This is also why stiffer spine arrows can be shot from a center-shot bow.
You probably will see a small area of wear on the strike plate, and the seal skin will wear faster than a piece of leather. If you like the look of the seal, use it.