Did my bellows last year. Not a hard job, laid my roof on a table covered with a quilt to protect it. I found the best way to do it (for me). Firstly make sure you have the aluminium strips in the right place. They are bespoke so my'n only matched in the correct places. I swapped out my brass nuts and bolts for stainless.
I found it best to use a small piece of welding rod sharpened to make a small hole before pushing the bolt through and putting the nut on. You could use anything as long as it's not to thick. I did the ends of the strip first and then worked in. Getting the corners right is essential.
I had been advised to double up the material but didn't as i felt it would have been tight once attached to the van.
The strips go on the outside by the way.
It took me a day to put the 4 strips on, wasn't to hard once you get into the flow. Scary at first as you don't want to rip anything. I didn't tighten up all nuts until the end. Hope that helped.
