With respect to the welding, at least you're cutting well back to good metal and going for it! Patching onto so-so metal will get you an MOT usually, but will be back to square one within a year or two.
As long as those welds have penetrated properly the loads will be transferred, compare with riveted, bolted or spot-welded constructions for instance.
Apart from a handful of areas around the jacking points, where they got the gas torch out, there's very little seam welding on the whole truck.
I think this whole thing about continuous welds has come about due to further rapid corrosion, not strength, load transferance per se.
If the metal is not pre-treated, dead flush and the welds de-scaled and post-treated back and front, most will know that MOT repairs of that nature are a breeding ground for moisture ingress and crevice corrosion. Even a continuous weld if not well thought through, will very often be rusted back through if in an exposed low body part, in say three years, maybe less if salt gets in there too. and water can't drain.
If you haven't arranged to get to the back of the weld afterwards, then there's trouble in store sooner or later, usually sooner... MOT testers know this, but are more constrained now on knocking your tinware about to check. It's more often today it seems, doing a proper job for yourself, as they can't see into closed sections -
I just had a car failed on all the main front-rear brake lines on corrosion that were barely touched by surface corrosion in a couple of places - no pitting corrosion at all - and a hell of a job to change them, yet... it was then passed when I could push my fingers through the sills (a previous MOT repair )
I'd rather they suggested I clean and treat the two small spots of rust on the brake pipes, and repair the sills properly! But, that's life, a difficult job for them without stripping the car down to nuts and bolts!
Try to make sure that every area you repair has as much resistance to water entering and staying there, and as much possibility of it getting back out when the weather turns and it can dry. I'm currently using Dinitrol RC900 on back of welds and inside sections, if I can't get a spray in there I pre-make a hole so I can (with a doubler plate if highly stressed area). And then a chassis type paint and then later when all is done, a heavier Waxoyl type of spray. Plus a few extra drains. Blocked or inadequate drains seem to be where it all starts to get really bad...
e.g. The original (VW) swaged hole in the rear-cross member sems to be the wrong way around, for free-draining... This repair section is how I see it should be. Very easy to swage a drain hole like that...
. do u have a web site to order from cause u guys have given me hope, Nice 1