I do the same thing Peter. I have never tried to use a cap over the hood. The squeeze caps work so well, even inside a deep hood.
As Brian mentioned the LC-72 cap is not a perfect fit over the HN-1. Actually I find that it's not a fit at all unless you remove a little material from the cap. It's just too tight and you risk it popping off the hood. It is a perfect fit and stays on the HN-2 and HN-3.