Hey Bill,
Last year i replaced the soft top on my ’66 Alpine (which should be the same as the Mk.1A/Mk.2). Also got the top from SS. It came with no straps at all!!
It’s fine with the windows up, but with them down, the top (of the top) buffets around so much at highway speeds that you’d think it will either rip apart or get really stretched out.
I would definitely put some supporting straps in (the more the better) before installation.
Still haven’t decided what to do about it – can you retrofit straps in after installation?
(Luckily i only use the top in winter with the windows up – natch).

Rob (rootesrob)