Just some advice on "can" size. I find that more often than not, you need to reduce a can A LEAST 50% to achieve a solid, flaw free billet...and that's assume you make no errors along the way such as Fitz mentioned. The reason I bring this up is because IF you start with 2x2", then take it down to at least 1x1", then remove the can, you're almost certainly going to end up with less than 1x1". Now, that being said, there are of course other ways besides forging and maintaining a square.
I know some folks who don't have equipment large enough for 3x3" or bigger, and are very good at building their "cans" from side.... something like 1.5-2" thick X 2" tall X how ever long they want a blade to be.... and then one entire side is the lid. Then they only forge on the 2" sides. I've tried it several times, and just never had a lot of success, so I stick to my monster sized cans.
I don't think that squaring dies are actually a must, nice yes, but not absolutely necessary. If you can control your press effectively and precisely, flat dies work, although I would recommend using stop blocks as an insurance policy.