I have the Harbor Freight Lift. You don't need the adaptors. You do need some longer bolts, you can buy them at the Hardware store, to allow you to move the lift pads to the outside of the lift braces. Make sure you turn the bolt by the dyna kick stand the other way if they are longer than necessary.
See my profile albums under Turn signal relo for further explain photos on the lift. I used 1/2" plywood pads with leather strips on mine, works great.
*! Buy the extended warranty on the lift, it's less than $10 bucks. My Jack started leaking fluid after I jacked it up all the way with no load. They gave me a new one. *!* Save you old bolts, you will have to put them back on and switch the pads back if you exchange for new jack on warranty.
It is a great Jack for $80 bucks plus warranty. I use mine all the time.