Extrude Feature "From"

I created a Boss Extrude feature and used the "From>Offset" to start the
extrude. How can I control this offset distance outside of the extrude
feature properties (equation, DT, etc.)?

Also, while I am on the subject, has anyone ever got the "From>Surface" to
work? I have never had any luck with that. If I could get that to work, I
would not need to know about the offset thingy above, but would still like
to know if it is possible for future reference.

--
Seth Renigar
Emerald Tool and Mold Inc.
(Remove ".no.spam" from my address)
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