I installed my vinyl top twice. The first top had a bad seam which wasn't realized until it was installed. I used 3m super adhesive bought at local parts stores at $25 per can and it took three cans. After realizing that top needed to be replaced, I pulled the whole top off in a matter of minutes because of poor adhesion of the 3m product.
Knowing what I learned I decided to dig deeper to find a better adhesive and ended up using Weldwood brand and sprayed with an old gun. Cost was $35 for a gallon. This adhesive is super strong and top is here to stay. There aren't any second chances so you need to have a game plan down when installing.
I don't think the brand of glue used is the issue for most installs, as long as it's a quality adhesive, it's technique and application that often lead to failures, I've been installing vinyl tops for over 3 decades using assorted glues over the years including Weldwood/DAP's products, and the 3M Super spray adhesive you mentioned(which I prefer)I've never had an issue with either product, but have seen failures with both, and other mfg's products when installed by others using techniques or application other than the methods I learned in the trade, hence my earlier recommendation the OP find another installer, the Gator grain top is not your garden variety vinyl top that can easily be replace (cost wise) if the installer FUBAR's the install...
FYI I have 3 cars in my collection that have vinyl tops that I installed using 3M Super spray adhesive, the oldest install over 2 decades ago, zero issues with both, I still use 3M Super spray adhesive to this day for vinyl top and upholstery installs, IMHO the same product/quality it was 30 yrs ago
Mike
