Ok actually reading about the Vickrey auctionVickrey auction made me think of the Jim Ratliff's answer made me think actually noit's LESS fair:
If Hikaru wants to go for as low as 9 minutes, but Magnus wants to go for as low as 6 minutes, then maybe we'd just end up with that the final bid is - let's say there's a minimum of a 10 second difference between bids - Magnus with 8:50. Hikaru won't go lower, and then Magnus has a 3 minute advantage.