Not sure if your bolt pattern is the same as my 1400xl, but I put 4 five inch wheels on. All four lock and swivel.
5 Inch Caster Wheels, Heavy Duty 5” Casters Set of 4 with Brake, TONSUM No Noise Polyurethane (PU) Wheels and Safety Dual Locking casters, Swivel Plate Castors (Two Hardware Kits for Free) (5inch)
I can't seem to make the link work. Bought at the big river.........