Would like to shoot cheap 55 gr rounds and the 77 gr as well.
BDC reticles are really only intended for one load, because the distances and drops are going to vary from one load to the next and even from one rifle to the next. That said, Nikon has software
you can use to run the drops based on different loads as long as you know or can estimate the velocity of your ammunition. So there's no reason you couldn't have data for two different loads if you want, as long as you know the drops will be different. And as far as zeroing goes, you can still zero your crosshairs wherever you want and then use the drop points accordingly once you figure our where they are approximately. I'd agree with Crow Hunter though that one way or another you'll want to actually verify your zeroes after you estimate your distances.