If you cut the regular, then there is the issue of how to join it properly and not have leaks. I would not recommend this. I don't think such an extra long hose is necessary as taking off the mask and putting it back on is much simpler, safer, and does what it is designed to do.
You seem determined to do what you want anyway so have at it. Just keep watching the data and the leak rate.
Apnea Board Moderator
Breathe deeply and count to zen.