Welding body seams

yeah id love to tig weld my pannel in ive been practicing but man i dunno if i could do that, i'll definatly having to pick up a flanaging tool for my house shop. where did you get your body pannel(qt pannel) from? it looks like the exact same metal as my fender patch and it didnt fit for ****, also anyone know who carrys the black (finish) qt pannal, my dad had one of these for his challenger and i believe it fit pretty well?