I would like to put an arrestor in the line but recommendations are
sketchy even from those who sell them. I assume it would be most
effective at the base of the tower on the ground rod. The drawing in
the ARRL Antenna Handbook shows the arrestor on a common station
ground.

Once you have more than one or two antennas, disconnecting the feedlines
and throwing them out the window gets to be a real pain.

you probably want to

a) ground the shield of the coax at the base of the tower, and
b) have a lightning arrestor where the coax enters the house or at
your shack, and
c) connect the grounds of the tower, shack, and power co. together

I ground the coax shields at the base of my towers, run the coax
underground to the house, and then have lightning arrestors at the
house before the coax goes up to the shack on the 2nd story.

Tor
N4OGW