Loaded tires are the best for traction and stability regardless of the transmission type used. You really don't want your tractor tires spinning all the time because of lack of traction. You wont hurt the HST transmission by loading the tires, they are designed to stall before any damage can happen.
I would suggest that unless you have a very good reason to need to move the tires in and out all the time, that you have the dealer set them to the widest point and then load them with fluid.
Unless the OEM limits loading of tires (my
B26 TLB manual says not to load the tires with using the backhoe), load them up. It is not impossible to swap the tires in and out when loaded but you do have to be diligent and keep them balanced upright when doing so.
On my LS P7010, I flipped the dish rims out and made the track as wide as possible on the front and then matched the rears up to the front. I could have made the rears even wider. Good thing I didn't though because as it sets the rear tires just squeeze in between the fenders on my trailer for transport. Something to consider when selecting a wheel spacing.