@TJ Ward I can only speak to Vintage, as that is what I’m familiar with. I recently purchased the Full Tonneau from Greg at Vintage, as my speedster only had the 1/4 Tonneau.
Vintage uses the button snaps (or at least did with mine). The original Speedster uses Tenax fasteners (German Tenax, not English; there is a size difference). Also, from what I read, the original Speedsters had “GHE” stamped on the Tenax fastener. This is no longer available. They will have “LOXX” stamped on them.
I wanted to replace the outboard button snaps on my speedster with German Tenax. I ordered (13) German Tenax complete sets for the rear (complete as in post and fastener head). VS uses the 2-screw fasteners immediately behind each door. So I ordered (2) 2-screw German Tenax posts for these locations and matching Tenax heads.
Given it’s a full tonneau, I need to install Tenax fasteners on the top of the dash. I purschased (5) complete German Tenax sets for here (posts and small heads; 2 on driver side, 3 on passenger side).
And, since the convertible “emergency” top has button snaps, I need to replace all them. So I ordered (15) Tenax small heads for the top.
Lastly, I ordered (2) additional Tenax posts and heads for the doors. Some original Speedsters have fasteners just forward the back of the doors to keep the tonneau cover in place (at least on the passenger side).
I plan on on keeping the button snaps on the interior of the car, At the corner of the windshield posts and on the inside of the rear cowl.
I’m not going to lie. Tenax are $$$$$$. The cost of the fasteners and shipping exceed the cost of installation.