david weaver
...by the way, I think you should stick with a one-piece plane for now. If i'm thinking wrong about the wedge and abutments, and you want to do your mortise straight sided and just use a cross pin and wedge or a lever cap, you can discard my comments about the abutments.

But at 3x3, you'll find things are pretty tight to get a 2 inch iron or a little more in a finished plane, and a plane of that length you'll want at least that.

a 4x4 blank is a bit more comfortable to start with, but I know as well as you do finding a blank of that size that's rift or quartersawn and isn't exorbitantly expensive is TOUGH to do. 3x3 blanks are out there for bats and table legs in droves, and don't cost too much.

Good luck!!