So, on the topic of mirror cells: I've built one of Berry's scopes already, and I like his ideas of mirror support using silicon adhesive; it seems to work well on my current scope. I also read the 2 part series in Astronomy mag (Jan and Feb of this year) on building your own scope, and those articles have some interesting ideas as well.
I'm planning a 10" f/6, and here are my current plans: The mirror is held to the mirror support a la Berry; with silicon cement. This provides a strong yet flexible hold, support from the edge as well as the bottom, and I can use as many points of support on the bottom as I want.
It is the connection between the mirror support (a 12" disk of wood) and the... whaddyacallit... the mirror support base (another 12" disk of wood), that I can't decide on. I think I'm inclined to go the screw-and-springs route, with a central pivot point. This way, I don't think I'll need push screws. Also, I like the idea in the mag. article about 4 adjustment points over 3 to make alignment easier.
If anyone has opinions or experiences to relate, I'd love to hear them!
-Dave