The wellnuts are M5 around the fairing joins and M6 underneath and the one each side on the frame mount.
I buy them in bulk from a fasteners supplier. As Yeti says, they are used in the building game
The DZUS conversion is, as Rockhopper says, a lot of hassle, and in truth, after some practice not that big a time saving. The problem is that the nose still has to come off first to remove the sides.
I'd fit new well nuts, use stainless fasteners and assemble with plenty of copa-slip.