Hmmmmmm, The spiral dive is exactly what you don't want! Think about it, your in the soup, cranked over holding your spiral and the airspeed keeps building. What do you do? Pull back to slow it down, right? There is a name for that situation, its called a dead-man-spiral.
I'm for pulling the spoilers, trim for 65 and turn loose. Try it next time you have extra altitude. I once logged something like 30 minutes in my H-301 Libelle (spoilers closed), she never went over 45 degrees and I hadn't touched anything for 30 minutes.
JJ