AndyS wrote:
*** The main reason for the question is my wife's opinion of acceptable
adornment for the exterior of our new house...... She doesn't share
my fascination with "electronical stuff" as an art form...

Well that settles it in my mind, do it inside the roof as high as u can get it.
(use rope and pulleys so u can later play with it, when the urge hits)
It should work almost as well as of it were outside and 3 foot higher.
Easy to get the feel line to come away at a 90 degree angle.
(not necessary, but if it does great)

and last but not least
It will save up your exterior adornments play with the xyl for a later project.