ATM 4" newtonian

[zoso@sccoast.net]

i have a 4.25"f/4 mirror and a 1.5" secondary that i want to build a small,
compact newtonian scope.  i have the following questions if anyone can help...

1. is there any problems in using pvc pipe for a telescope tube?
2. is there any need for offset in the secondary using the listed optics?
3. what is the shortest length i can make the tube?...i have read that
subtracting the distance of the secondary mirror to the focal plane from
the focal length gives you the distance from primary to secondary mirror,
but was unsure on this subject.
4. with a small primary mirror, would there be serious problems with
glueing the mirror to a a metal plate for a mirror cell?

this is my first attempt at building so any help would be appreciated.

thanks, becky