I got
my casters from enco. They are the larger ones with the brake, and I got free shipping (coupon). Could not ask for better casters. They look like the same as what you got.
Pic 1
Pic 2
6"x2" Steel w/poly outer. 2/3rds weight on all the time and they will not flat-spot. They roll good on grinding dust too
Table looks good! I have my legs cut-out and a 4'x5' 3/8" top I plan to use just haven't had the time, and currently no room for a bigger table

Having EVERYTHING on casters sure is nice I`m sure youwill love it