I would tally up how much it will cost you to ship the bags with the airline, then check to see how much it would cost via ground shipment. The reason that it is so expensive to check excess bags for an airline, is that when you do this, you are treating the airline as a freight forwarder, so you pay the applicable costs. Companies PAY for space to ship freight on airplanes, as well as the post office. They book to have guaranteed space, you in effect could be taking up space the airline could sell for a higher price
If you do not need some of the pieces immediately, save your money, ship by ground
If you do send by ground, ensure they have you purchased the appropriate insurance for the pieces just in the rare chance they get lost