Cards in the front row is simple and easy and may be the best way to go simply on that account. But if it interests you to figure out what works best, I'd certainly give the catwalk a try. Hanging spaced omnis over the conductor position is a commonly prefered way to record professionally in a concert hall. You can do it like the pros do. Most here will never have a chance to record that way. Personally, I'd jump at the chance!
Compared to recording from the front row seated position, from a hanging position over the conductor the orchestra will sound brighter and generally clearer overall, the instruments in the back rows less distant and reverberant, and the audience reaction more distant and evenly diffuse.
Use the level settings which worked for you previously from the front row, maybe with a touch more headroom just to be safe.