DOUG,
Depending on how you build the 'hazer', you really don't need
rails. The thing will slide up the tubes of the tower just fine,
won't even bump on the bolts (much). Also sort of depends on just
how 'much' antenna is used and how often it goes up/down, since
there is some wear on the tower. 'Normal' use shouldn't be any
problem though.
A friend built one for me. Not aluminum, and aside from building
muscles I didn't particularly want, worked fine.
'Doc