If you could get to the front row of the balcony and hang the mics over the rail...

Agreed on cards if you wear them.
But why settle for mediocrity when the opportunity for greatness presents itself?
If you are adventurous and want to try something interesting you might consider wide spaced omnis mounted
on the front balcony surface.. I'd not hang them below the edge but purposefully tape them directly against the hard surface, widely spaced, in the flat areas right above those architectural 'M' shaped molding features in the photo above. That would boundary mount them and work the seemingly magical +3db increase of direct sound over ambient pickup thing that boundary mounting does, which I've had great luck with for placing omnis much farther back than would normally work. Focuses the direct sound from the stage and PA and cuts down on reverberant room sound dramatically. It's also directly above the sound mixer's position and not up in the potentially echoy balcony seating area where the sound guy's ears are not.. and it's far enough away from the crowd for a much better AUD balance and the wide spacing will give a fantastically even, wide & enveloping crowd response. If you can work that I'm willing to bet it would not only work great but will outright smoke a HRTF recording made from the middle of the crowd in the upper balcony regardless of what mics you could use up there!
Come on, try it! It's a perfect scenario for this, really!
..unless it's a strictly low-profile gig.