OP, I'm curious how you made out with the corvids.
For some reason, I only noticed your post just now. If you're in an apartment as you describe, I don't see why you'd regret attracting crows. I'm quite a fan of them myself, and their cousins the ravens too. They're very wary following many years of persecution though, and it's hard to get as close to them as to some other species, specifically to get them to come to feeders (unless, I assume, you don't want them around, whereupon they no doubt pile in and take over). As with any bird, it'll probably take (or have taken) quite a while to get them to find and accept your feeding setup, so patience is the keyword. I've had my present feeder setup for about 2.5 years now and crows come in occasionally, to check shiny objects I think, but I don't really have anything to offer them and I know from other setups that they tend to scare off smaller birds.
If you didn't see it, take a look at an item I posted from the BBC on this very forum, 'the girl who gets gifts from the crows.' Crows are definitely intelligent and little understood animals.