As a point of reference for you. This is my Prime 4 EVA bag compared to two standard overhead carry-on bags. Height is about the same, width is a bit smaller, and length is roughly more than the two carry-ons side by side.
Call the airlines and check thier musical instrument policy. They do have provision for instrument carry-ons, check at. the gate, and (worse case) purchase a full seat for your instrument.
Keep us posted, good luck, and safe travels!
