[Artisan]

When you use different tape you can shape it around the edges of the mirror so the points of contact are greater. I am just concerened that the 3M heavy duty is still not strong enough for extended use. This makes the argument for caulk if you are not going to use different adhesive. At least you know there is an option... I would say you should put some caulk behind the mirror still so you can be sure there won't be a problem.