In addition to steaming there is also the factor of how well they fit in the goggles.
If you can then take up the offer of trying some, or try to get to one of the retailers to try some on.
An alternate depending on the glasses you already have is to get another cheap compact pair to make them easier to fit in. Or depending on your eyesight consider the need to wear them - if like me I need glasses for distance but can see well enough to see how close I am shooting, so often don't bother with glasses.
Once you have goggles & glasses then there is still the risk of misting, but other options such as fans & anti mist solutions. A decent set that you get will be better than the sites standard set, however some sites will have goggle options to let you upgrade or buy a new set on the day which will be better than the same set that have been used by punters every week.