I wouldn't use the narrow crown staples. I did that a few years ago when repairing my Springdale and they tend to pull through the aluminum after moving the camper a few times. Plus, I was using a pneumatic stapler and it was extremely difficult to get the air pressure set right. The different density of the wood behind the aluminum would allow the narrow crown staples to work some times and other times they would punch right through the siding. Ended up using a wide crown stapler with the longest staples I could get.