Dan I made the leveling pads myself out of hockey pucks, 5/8" bolts, jam nuts, and washers. Hockey pucks are great for leveling pads, pretty much indestructible. I have industrial machine leveling pads rated for this weight, the hockey puck pads are much beefier.
Now here's the bad news. First the slot holes for the level pads in the bottom of the lathe stand are so large (about 3/4 inch) the puny 3/8" studs for the industrial leveling pads for this weight are way too small. You would have to stack a bunch of fender washers together otherwise they would just bend into the slot as you tighten them hence the reason I went with 5/8" bolts. You could go with larger industrial leveling pads but that gets very expensive fast when you start spending $30-$60 for each pad. There's more, the lathe stand is WAY too tall to begin with and even using thin jam nuts you will add another 2" in height to an already too tall stand. My brother and I took some measurements (he's been a machinist for 25 years) we figure the lathe stand needs to be cut down 5-6 inches in height vs on the pads its on. Also as you can see in the pics the pads are located well inside the stand which makes it tippy front to back. Its not going to tip over in use most likely but I have been in a minor 5.0 earthquake and could see it tipping right over the way its setup now.
So honestly I would not use leveling pads at all, I would set it right on the floor and shim it level. My garage floor slopes substantially but I only have about 1/4" different in height between the rear and front leveling pads as pictured. I'm going to remove these pads from my lathe soon and shim. I may put the rear down on a thin rubber pad then shim the front to level. I'm not too bad side to side level wise so I think I'll be okay there.
That's my 2 cents worth.