Without a doubt you need to use Mil-Spec Tefzel wiring in all
aircraft. It isn't all the expensive and required as far as I
know.
The jacket is tough so that is isn't easily abraded causing
sparks
and fire. If there is a fire the jacket resists burning and
doesn't
emit toxic fumes.

For all of these low current applications that you mention,
anything
from 22-26 and smaller gauge will work - the smaller the better to
a
point). Look for multiconductor to save yourself some additional
wiring. Below are some sources. You don't need shielded in a
non-
motorized glider IMHO. No ignition system!

http://wingsandwheels.com/page5.htm smallest is 22gauge
http://www.aircraftspruce.com/catalo...es/wc2wire.php 5
conductor 26 gauge
http://www.aircraftspruce.com/menus/el/wire.html smallest 24
gauge
(I don't think that http://cumulus-soaring.com carries Tefzel wire
as
yet)

Lastly, as to gear/spoiler warning you need to make sure that you
are
not interfering with the regular operation of the glider with
switches/
wiring and need to be very careful if you are planning on drilling
any
holes. General, most gear warning systems that I see use
mechanical
micro-switches (http://cumulus-soaring.com/misc/switch-
lever-1.jpg).
These have to rub against something to be activated (where
exactly?)
which can lead to wear where you don't want it. I prefer magnetic
reed switches (http://cumulus-soaring.com/hamlin.htm) which don't
have
any wear points as they don't rub against anything. When a magnet
gets next to the reed, a "switch" is closed or opened (depending
on
how you have it wired). You tape or glue (I prefer non-permanent
solutions) the magnet to the airbrake and gear mechanism somewhere
(trial and error part) and glue the "switch" to an adjacent
surface.
Easy.

Full disclosu For standard airworthiness aircraft you need
someone
official to sign off on this mod. As I understand it, if you
didn't
build 50% of your experimental aircraft, I think that you also
have
to have have someone sign off. My $0.02. Stay safe.

- John DeRosa "67R"