SPACEKEEPER Workbench Casters kit 660 Lbs - Retractable Casters Heavy Duty Bench Caster Wheels Designed for Workbenches Machinery & Tables, 4 Pack

Well done. I’ve made 3 of these and learned so something on each. You will enjoy it I know. One thing I’d recommend is looking into some flip down casters like these: https://www.amazon.com/dp/B07QRH8VS2?ref_=ppx_hzod_title_mob_b_fed_asin_title_0_0

https://www.amazon.com/SPACEKEEPER-Workbench-Retractable-Workbenches-Machinery/dp/B0CF146HDL might need to build a box or something for the base, or maybe fill with concrete and anchor those casters right into the side.

https://imgur.com/a/tRDDe2g retractable casters I was lazy and didn't use all 4. Works just fine. No pilot holes with those sheet metal screws. Just drilled 'em on in.