Center Seat Belt Modification Plan. Advice Needed

[OllieNZ]

Hi All
Now I have access to a welder Im going to swap my rear center lap belt for a lap and diagonal and Im after some advice.
I want to keep this as simple as possible so my plan is to weld a bar just in front of the rear seatbelt hanger attachment bolts up near the roof and attach another seatbelt hanger to the bar.
Now for the questions
Will this area be strong enough to weld to?
Round or square bar?
Material spec?
Would I be better off welding the bar to plates on either end and then drilling and tapping into the sides and bolting in?
Im not worried about removability.

Thanks

Ollie

[OllieNZ]

Finally had some time to sit down with a beer and do a drawing

The red bit is the proposed bar
The blue bit is a stock seatbelt hanger
The green bit is the seatbelt
My main concern is attaching the red bar to the vehicle.

Ollie

[blackpoolsparks]

why do you need to go that high?
How about a bar just behind the top of the seats

[OllieNZ]

A couple of reasons:
I still want to be able to fold the seats down and use the full load area and I figure that if the stock seatbelt hangers are mounted up there that part of the structure should be pretty solid. A bar across the seat back would need to be about 2-3 inches higher than the head rests to get the seat belt to come over at the right height.

Ollie

[legendgamesmaster]

run it past an MOT tester too....

[OllieNZ]

Checked with a couple of local ones no problem apparently.

Ollie

[blackpoolsparks]

Another idea would be to copy the set-up used in a van.
Too difficult to describe, have a look at an MK6 or 7 Transit.