SARGE,
Depending on where you live and your weather, I would do as suggested, use a fairly heavy duty mast. Actually, if this is going to be the only antenna on your tower, and since it will already be at 60 feet, I wouldn't bother using any more mast than it takes to mount the thing. Another 10-15 feet really isn't going to make much difference and just adds another failure point.
The mast sections you already have would work okay, in all likelyhood. Not sure how you would go about using the guying rings, though (where to connect the other end of the guys?). I do know that ~here~, you'd really be asking for trouble.
Good luck!
- 'Doc