Looks nice! I can't tell from the pics what holds everything in place. Do you pin it after you set it on? One thing I don't like is the acetylene laying down, yes I know it is tilted but it should be upright.
2"x2"x1/4" tube running the length of the truck on each side welder frames bolt to 3/8" bolts x 4 for each welder 80K miles no problem. As for the tank I have heard that they will explode for 40 years but have not had any problems. Can tell you how many jobs I pull up on and there is a guy in the gravel cutting re-bar with tanks laying flat on the ground. With the Spectrum 375 Plasma on board very seldom use it torch.