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I find it hard to think in sq inches tbh but pairs usually do better in smaller cages, the larger the cage the more chance that they will become territorial over areas of the cage so at least until you get to know them & have a good idea if they will get on a smaller cage is better, no guarantees there as many pairs fall out as they mature so whatever cage you have be prepared to have another ready just in case they need to be separated.
Cages for pairs should have no levels, houses must have more than one exit & it's better to do without food bowls & scatter feed.
When you say dwarf hams do you mean Russian hybrids?
They generally do better living alone, it's more natural for them to live a solitary life & removes all the potential stress of fights.

If you changed your mind & just went for one ham that cage would still be big so you would need to give a lot of thought to your set up as some can be very intimidated by that amount of space, I have kept Russian & Chinese hams in 100x50cm cages which they loved but only after I'd had them a while & knew they would enjoy the space.