Yes, the guys on instagram, etc make it look way too easy.
I have A LOT of time in this bedside, but I'm happy with it. I haven't fully finish welded it, but the tacks are down to +/-1/2" apart.
I went with the Z cut at the rear because I wanted to eliminate the markers from this bed (my truck is a 67),
This thing was my best friend. I was constantly checking for flatness. I let a few very very minor dips go, but if anything started to pull in too much or push out I worked it, or cut the weld and tried again. It will definitely need filler to be super nice, but shouldn't be anymore than +/-1/16 in most places.
I did a lot of practice welding on an extra bed floor I had. It's a nice clean floor, but the blue floor was absolutely pristine and I didn't want to mess it up. Came out nice though.
Blue floor:
