Some sellers like to peddle these as winterisation or arctic kits which is nonsense. They would be pretty ineffective for that, the thin foam is just to give some support to the aluminium covering.
They were only to be fitted to FFR vehicles for RF radiation protection purposes. Although I admit they are also quite handy for reducing condensation & giving a more cosy feel to the inside.
Kits for the 90 are out there but extremely rare at the moment. I fitted the 110 kit to my 90. The front piece is the same, but you need to omit the middle section as the rear section has the straps. You will find rear section will have quite a few gaps but will do until the proper thing turns up. With my middle section I cut it up & made blackout pieces to go inside the windscreen & side door windows.