From my latest sketches, it will be 14mm x 28mm. It's just a 4wd rambot to get me into the game, next up would in theory be a melty brain using some multirotor tech (the idea of it being able to "jump" has crossed my mind!).

Angle grinder with different blades would probably be the cheapest way to go. Just found out my neighbour has a decent mig welder he's never used so will need to learn how to use that soon.