Why not make it what you can hold or what you can fly: Whichever is greater?

That way the senior guys can fly the domestic stuff, and the junior guys can fly the heavy INTL stuff, but not at a severe discount to the CO. This way you can pick for QoL/type of flying, and not take a hit for it.

It somehow works for UPS. I do know you have to be senior to get the domestic stuff there, though.