My Speedster’s tonneau & top were fastened to the rear deck by tucking the rear of the tonneau & top under a trim around the rear deck. Although clean looking, took too long to transition from tonneau to top. I finally got around to installing conventional fasteners.
I used Easy Fit pins to position the fasteners. I used Loxx (similar to Tenax) pull up units. Although kinda pricey, both worked really well. I can’t speak to the durability of the Loxx units, too new to rate, but they are polished stainless and seem stout.
I have some experience with leather work (gunbelts & holsters), but zero with tonneaus & tops. The Easy Fit set up allows for positioning of the fasteners so everything is nice & tight. There a bunch of Youtube videos on the how tos.
Both are available on eBay.