I'm late to the game, but 2x2x1/4" is right on point. It's actually 50mm x 50mm x 5mm. I agree with the oversizing too.Not super critical for the leg lengths, thickness for rigidity perhaps? Front leg is as short as possible to keep interference to a minimum
I would guess 2x2x1/4" or similar metric dims. Just go grab yourself something similar and match up the hole pattern.
You can even oversize the holes to make alignment that much easier on yourself
Good luck
