nice work! i'm envious of the sandblaster, i could have really used one of those for similar projects (also from that same day, go figure). I guess you have no way of getting to the backside, but i had great luck with a copper bar behind the sheet to help with the welding.
Tim M Hovey
1950 cj3a (soon to include more FJ parts than CJ parts)
Pirate4x4.com Build Thread
Disclaimer: I don't own a yota, but I happen to think they are cool.