I have a Top Cap with pull-pulll on the rudder and elevator. I struggle with just how much tension should be on the cables. Is there any good rule of thumb?

Tight but not guitar string tight. If they are new they will stretch a little after the first few flights so leave room for adjustment when setting up the cables.

hmmm, think in these terms:

Taught, but not tight.
Firm but not rigid.
Solid but not hard.


Dang, sounds like pornography...