As a veteran airline employee, above all else...DO NOT I repreat DO NOT CHECK YOUR MODEL AS BAGGAGE!!!
I agree with Pete about getting the max carry-on dimensions and shrink it an inch in each dimension. Have the package assembled so that it can be easily opened and inspected by security, even proactively approach them before you put it on the x-ray belt and tell them what you have. When you get to the gate, beg, plead, bribe the gate agent to let you on ahead of the dreaded "Zone 4" herd, or you'll likely not find any avaialable overhead space for your package.