This won't help all that much, but art.com once told me they use fedex all the way around, even for large pieces, using fedex oversize rates (?)
I do appreciate the response. Trouble is FedEx Ground/Home Delivery has two limitations on the largest box size. Their maximum length is 108", and their maximum length+girth is 165". (Girth is 2 * (width+height), or how big "around.) This is even on their oversize 3 rating, which is their maximum.
The max length+girth of 165" is tricky. A 38x82x3" package gets to 164" length+girth. And, that's allowing 1" of packaging on each side, and 3/4" on top and bottom (assuming 1.5" bars.)
Any more packaging and you bump over the 165" max, forcing you to go FedEx freight.
FedEx 3Day Freight (slowest on website) has a price of $960.70! (39x82x3) I know you can get gigantic FedEx freight discounts without needing a high volume account, like 60%, which brings it down to $384.28. But that's still with virtually no packaging.
Shipping it as a 46x90x8 lists $1195.70, with discount $478.28. That gives 4" packaging on the sides and 3.25" on top and bottom. No experience with how much packaging you need for FedEx freight...