I believe you may need something underneath the pads, however if you can afford it (I know theyre not crazy cheap) But pampers do disposable baby changing mats that come in a pack of 12 for £4, i find I need a total of 3 for my cage (i have a 2x3.5 base cage and a 2x1 hayloft) I only recomend these as i found newspaper made it smell fairly quickly.
I dont however yours inco pads and would be interested to see how others use them (ie if another base layer is needed)