Try A-B on stage like omnis, the slight directionalilty can help manage the level of front row fan exitement and bring a bit more presence to the on-stage instuments.
They don't really have enough directionality to make X/Y work well IMO, unless you want a very stable center-heavy mono image. Generally I'd go for increased spacing over increased angle, though the two are interrelated of course.. just somewhat less so than cards, and even less so than supers.