For centerfire matches I use 15x binos, which offers perfect magnification and it translates well for getting behind my actual optic for a stage because I shoot everything right around 15x.
For rimfire matches I've found 15x is just too much. You end up having to pan on your tripod to transition between targets on a stage because you don't have enough FOV on 15x binos. For rimfire matches I use my 10x Sig BDX 3000s, which works out twice as nice because we use them to verify range on targets as well. If you've got $1k, I'd highly recommend the Kilos so you get the ranging functionality and a great bino that can be used to spot both rimfire and centerfire matches if you wanted to.