Winter Storage - Top to be tight, or loose?

[Dave80GTSi]

Opinions, please - I have heard both options recommended.

For those of us with a secure but unheated garage for cold winter storage, have you made it a practice to park the car with the convertible top latch undone so that the top is slack?

Or instead, do you park it with the latch fastened so that the top is tight?

Does the rear window being either plastic or glass play into this question?

Thanks - DM