Any Ideas?

So, here’s what I need help with:
We are making Nest Tubes out of PVC Pipes, but I want it to be a good quality Nest Tube that helps fledglings leave the nest. On All About Birdhouses, on Features of a Good Nest Box, it says to help fledglings leave the nest, you can cut grooves into the box to create a “ladder” with “rungs,” or you can staple hardware cloth to the sides. Problem? The staples won’t go through a PVC Pipe, and we can’t reach a saw inside to cut the ladders, because the pipe is to small in diameter.
Any Ideas?