No advice on the taping as we haven't ever had to. Sorry.
But I agree that you're giving the girls too much space while potty-training. We crate trained first, and then moved into the kitchen, and now, with Coby at 7 months are beginning to give him more freedom. Also, we have two dogs and they do not use the same puppy pads. They actually seem a little disgusted with each other's pads. So I'd also try two pads. Maybe your second girl is jealous and would love her own pad!!
