If you have a mohair hood you will find you don't need them as the fit is far more relaxed than the Everflex where the tensioners are very helpful particularly if the roof is cold and tight.
That depends on your "mohair" (canvas) hood. It had shrunk on my '76 making hood fitting a painful experience - there are a few on here who know how blinking difficult it was. I was going to fit hood tensioners, but:-
Very useful as long as you don't have a bench seat in your 1969 4/4
Kind regards
Arwyn
Arwyn beat me to it they would have put too much side load on the mounting points. I sold them to Owen (bilibib) eventually.
It may be feasible to make your own Mandy, along the lines of some homemade ones I saw on Frank Orton's 4 seater but you'd have to be careful not to trap fingers when using them.