Getting comps on multi-families to see if BRRRR will work?

[Chris Low]

Like many people, we're intrigued by the BRRRR strategy because it combines the best of both worlds: accumulating buy-and-hold properties but not tying up all our capital. But our preference for buy-and-hold properties is small multi-family (duplex, tri & quads). Unfortunately, those can be difficult to get comps on and if you can't estimate your ARV, it's hard to run the BRRRR calculator with any hope of accuracy. So my question is two-fold: what's the best strategy for getting multi-family comps and do these properties typically make for good BRRRR candidates? Any help will be much appreciated!