Weld 2 tubes from a-pillar to a-pillar (a-pillar is the pillar where the door hangs on) and fron b-pillar to b-pillar (so from side to side). Than you weld 1 tube from a to b-pillar on each side.
This will hold the body strong when it is going bodyoff..
I'm also in body-resto (now for more then 2 years
)
Greetings Wiebrand
p.s. weld the tubes so low as possible BUT keep in mind not to low if you have to change your heatingchannels , etc.