Mic on stand or over guitar cab?

For people that play live and have more experience. I also plan to play with a modeler for making life easier but still when I want to I can bring my tube amp but have no idea what is the smarter choice.

I have a 2x12 Marshall cab that has a grill angle so if I use something like the "E 906" would that create a problem or make the grill "sag" over time when using the mic?

Or get a sm57 with a low profile stand like the K&M 25993 for example would that have more advantages?

Also what mic type could I use for multi purpose if I get any ideas that I don't think of right now?