A) I would not want metric studs. B) Will a 64.1mm (2.52") center bore fit your hubs/axles? C) While 100mm is close to 4" it's off a little, like .063". Might get away with it, but when the 100% correct ones are easy enough to find, why bother?
5x100 is not the same as 5x4” and a 64mm hub bore will NOT clear the hub registers even on a SBP car.
The seller of the other adaptors is just trying to get out of taking the adaptors back if they don’t fit. Those application lists on eBay are notoriously inaccurate.
If the adaptors will fit a SBP Barracuda or Duster like they’re advertised to they’ll fit your Demon.