Torsion Spring or Extension Spring?

[FL Guy]

How are you attaching a mounting plate for a torsion spring on a sectional garage door to use in one of these tubular buildings?
OR are you using extension springs?

 

[jack stand]

I'm not familiar with these carport buildings, but in a wood framed building the interior of the opening is usually "padded" inwards 1 1/2" with a 2x6 vertically each side and a simple block attached (to the header) in the proper position to catch the mount.
I'd guess that you'd do similar especially with limited attachment points for the track and weather stripping.
The top horizontal "block" I mentioned should probably be a full width 2x8 catching hopefully 3 of the primary tubes that make the wall.

 

[cr-garagedoor]

The mounting plate should be securely fastened to the header above the garage door opening. Use lag screws and proper hardware to ensure a strong attachment. Follow the manufacturer's instructions to assemble the torsion spring components onto a torsion shaft. Mount the torsion shaft, and once the spring is properly tensioned, raise and lower the garage door to ensure it moves smoothly and remains balanced.

 

[dante2]

I used a 2" square tube cut to length and bolted between the headers. I used a piece of C channel on the first door but will most likely replace it with the square tube.