I use the X-chocks with my LaCrosse. You have to buy the extended version to work with the E-Z Tow axles. They are expensive compared to the regular ones. I found mine on ebay for something like $152 for a pair including shipping.
I don't think anything short of putting your tt on blocks will completely take out all movement, but they do make a difference.
You will still need some type of wheel blocks to hold the tt while hitching/unhitching the tt. The X-Chocks are applied after you have leveled the tt and removed before you hitch up.