I have a small job coming up in which I will be using waffle grid type icf. Does anyone have experience installing electical in this type of icf? I have always used flat wall systems. On flat wall systems, I always use metal boxes if the foam thickness is 2 1/4" or less and I use plastic boxed on icf's with a foam thickness of 2 1/2" or greater.  The boxes could obviously be mounted to the concrete anywhere on the wall with a tapcon. What happens in a screen grid type icf? It is unlikely you are going to find a flat spot anywhere in the wall to mount a box. I want to be able to mount boxes anywhere on the wall, I don't want to use the boxes with a flange and mount to the ties. Any input would be greatly appreciated.

Thanks!!