My mohair hood/top on the 8 had not been up for about 3 years, & not seen rain for a couple more, when I was caught in a summer downpour. Fortunately it went up easily enough, but downpour was right, the water poured in everywhere.
It ran in through the stitching around the rear window, right from the start. With in another 15 minutes it was dribbling in from the gutters over the windows.
After 20 minutes parked, getting back in was rather like sitting down in a swimming pool.
A wax bar rubbed into the window stitching fixed that, & 303 hood treatment sealed the thing again, but did give a sort of shine to the finish.
Next time I wanted it up, over a year or so later, was up in the ranges, at 5.30 Am on a winters morning. I had to get a passer by to help stretch the thing to get the pins into the holes.
Don't believe mohair doesn't shrink when cold.
The vinyl one on the Capri is much more water tight, but I haven't tried to put it up when cold.
Hasbeen