Vinyl Top in Cold Garage?

My 68 Dart is ready for a vinyl top install. I want to do the vinyl, then the headliner, than put the front and rear glass back in. I have an unattached garage with a pellet stove in PA.
Is it ok to put a vinyl top on a cold car? How warm does the garage have to be for the install? I don't want to wait till it warms up. Thanks for any advice.