Shipping floor standing speakers

Unless I’m missing something you should be able to ship them as-is in their original packaging.

Okay so you think they'll be okay...i don't need to palletize them.

When mine came in, they arrived on their side in their boxes without incidence. Another brand I bought arrived upright, on a pallet. The manufacturer insisted on that method due to the fragile crossovers yet one still had to go back for damage. I'm not sure the pallet adds anything other than cost

If your worried Double Box them. FEDEX/UPS STORE can make boxes for you if you cant do it on your own. Just pass the added expense to the buyer.

What is the weight?  If you go much above 70lbs per box, that is when the horrible handling of FedEx UPS creates a risk.

I shipped a pair of Zu Essences which are packed in like 4 inches of foam.  I assume FedEx dropped one of the boxes off the back of the truck and the base of the speaker was damaged.  
Palletizing and shipping via freight is better but far more expensive.  If you ship those LTL, expect it to be $500+ for freight.  
Best thing is to sell them locally.