I am at the same stage and was all set up (having read Eric's excellent description of the installation) with spray adhesive when an Upholsterer friend visited and recommended 3M double sided tape. I am not sure why I hadn't thought of it, as only days earlier I had had to clean off (its a long story...) a large amount of double sided tape from a bicycle frame. I can assure you it sticks like s*** to the proverbial blanket.....
Here are the results so far - seems to do a great job. I started off carefully positioning the side panels, holding them in place with masking tape, and then sticking the top 3-4 inches with tape laid around the perimeter of the sail panel. I then removed the masking tape, lifted up the lower section of the vinyl and held it up with more masking tape and then taped the rest of the perimete. Careful laid down the vinyl sticking one edge and carefully stretching towards the other edges. Finally I taped the sections where the vinyl folded over and stuck those down. The tape seems to "set" gradually and so repositioning is possible as is peeling off for a final trim. I was always a bit afraid of the finality of the spray adhesive approach, oh and there is no issue with overspray
The tape seems much more controllable. Time will tell on the durability but my upholsterer friend assures me it will be fine.
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