We have a rubber poker table mat that is considered “Large bulky” because the single item box measures 36.25 x 4.25 x 4.25 inches.
We send to FBA using LTL (pallets) only. Never UPS Ground, only freight trucking.
We ship 6 units per master box.
Master box measures 37 x 13.25 x 9.25 inches.
No issues with shipping master boxes of 6 units via LTL.
Side Note: remember, Amazon uses dimensional weight when it’s greater than the unit weight to calculate fees.