I'd make my current best guess at the opening day starting oline lineup and work as much as possible on cohesive line play, familiarity with linemates over any more individual evaluation of Tucker/Petitti or Johnson/Gurode. Exclusive snaps with first team skills personnel.
I really don't think much more assessment wise will shake out a sfar as what each brings to the table over the other. That's pretty much known by now. Really, what can Rob tell us about gutsiness he hasn't already and what degree of readiness will be shown in a week four preseason write off?
So even tho Riviera's hammy is still a practice limitation consideration, I'd try to get these guys gelling for the next two weeks. Serious bonding and nuance stuff so they have the best chance of knowing what to expect from each other.