I'd pick Grant. The pre-Lewis version of Grant was a lot more solid than Briggs ever was. Managed to stop David Izon and Golota, which is more than I think Briggs was capable of
Briggs. Miles tougher. Grant's not getting him out of there and Michael was always a bit prone to going down, even before Lennox got to him. The shots Lewis hit Briggs with would have finished Grant a lot sooner. Michael would need ti get Shannon out of the way before his own frailty showed itself. I don't think he had the tools to do that.
I mean what even is prime briggs? One round here or there? Guy showed flashes of brilliance but I can't even pick a fight the use as an example of prime briggs? So I'd go with grant by decision or late stoppage if briggs gassed out bc grant was more consistent tho ultimately disappointing