Chassis is similarish to the old SS buy the looks of things but if you use a 916 headlight mount (or lightweight replacment from ANR Performance) then it's just a case of some spacers (2 bits of ally with holes in the right places drilled into them) to attach it to the new chassis, then just make a few brackets around them, mine uses that, 2 holes into the original side fairing mounts and 1 ally bracket at the bottom to the engine casing on the l/h side
If you come to Cadwell track attack feel free to look at my 583 to get an idea of how you can do the mounts, a 620 can't be that different