You are at the mercy of the crew but I have noticed that most crews go out of the way to find space for instruments. Most e170 still have a small closet in the front but often times the crew has their luggage in there. As for the bins the first class bins you can just get a roller bag in with wheels to the back so about 22 deep and you can usually get four bags in a bin so assume something like 14 x 4. The larger bins are over the two seat side in first, coach you need to put the bag in the other way I am guessing depth to be about 18 inches and length 42 or so. I notice most instruments that go back to coach come back to the front for help finding space so I am guessing it is a tough fit.