Pam,
I have recently -- very recently -- learned about cutting vibratome sections 
and I totally agree that 10-20 micron sections would be tough. I did 40 
microns with great success on perfused brain, however.
Before I started I called Ted Pella and was advised to practice on 
hard-boiled egg white. So off to the cafeteria I went to buy an egg and amid 
lots of cracks about egg salad and the like I spent an afternoon practicing 
and the next day I cut that brain like a pro! The consistency of hard-boiled 
egg white was very similar to the perfused brain.
Practice. Yes, do practice.
Andi Grantham