[VEGAS84]

Looks like you're doing fine. There's no need to rush it.

Take the time to measure and fit everything before you final weld it. Try to remove as few parts at a time. Since you started with the cab corner, finish it, making sure it lines up in the exact same place the old one did. Double check the back, bottom, and along the door jamb. Then move on to the rockers and do the same.

You may want to reinstall the doors before you finish the rockers to make sure the gaps are good. Align them to the top and back (B-pillar) and then check that the rockers are in the right place.

Like Jakekelm said above, it just takes patience and it will come out perfect. Good luck, looks like it's coming along well, keep your build updated for us.