Don't get one big 'un, get two smaller ones. Otherwise you end up with one arm longer than the other and a bloody hernia to boot Plus with two equal size boxes they balance you up, and are a lot easier to move around.
I'm currently using the Swan flight boxes, and have to say they are truly wonderful, and they are very quick and helpful. https://www.swanflight.com/
they are quite simply the best. Not cheap mind.