The Tips can be Elevated above ground or
the Tips can be at/near ground level and a
Ground Rod placed at both ends (Tips) with
a Lightning Aresster (GDT) mounted on each.
.................................................. .......

The higher the ends above ground, the better.
You have less earth loss. There is no need to
use lightning arresters at the tips of the dipoles
to ground. If the wire were actually close enough
to ground to arc to ground, it will do it, arrester, or
not. Being as you are not protecting any devices at
the ends, there is no real point in using arresters. The
arrester should be in the feedline leading to the radio.
If the inv vee is supported by a tree or mast, the lightning
is more likely to take that path to ground, than the path
of perpendicular antenna wires to ground.
Lightning doesn't like to take sharp turns. So you should
always ground the supporting mast well, if it's metal.
It's gonna take the brunt of the strike to ground...
Horizontal wire antennas are not near as prone to be a
lightning target, as say a vertical, or other tall mast.
IE: a dipole, or inv vee hung in a tree will add little to the
overall likelyhood of that tree being struck.
It would probably be struck anyway, antenna or not,
if lightning was that close, to choose that target. I bet in most
cases, the antenna would basically be untouched, unless the
strike found the feedline running down the tree, and decided to
use it....You can always snub the feedline to ground at the base
of th tree in a case like that. I know I have had two direct strikes
to my mast supported my various dipoles, and have never had
any indication of wire, or coax damage.
That tells me most of the strike is carried to ground
by the mast, which does stick up about a foot above my
antenna apex. "I currently have 160/80/40 dipoles on one
feedline...Appx 440 ft of wire in the air...The apex about 42 ft
high supported by a metal mast. So far, in 35 years of hamming,
SWLing, I've never had a horizontal wire dipole be a lightning
target. But mine are never higher, than surrounding
objects, trees, etc unless supported by a mast, or tree, which
then becomes a more preferred target than the dipole itself...
Not saying it can't happen. It surely can.
But not near as often as vertical targets.
Even at 42 ft, I've still got trees taller than that in the yard...
That helps...The last strike hit the tree in the front yard....
If the vertical target is well above the house, other objects, you
can bet on it taking a zap sooner or later. Most people don't
have wire antennas higher than the surrounding trees, etc,
unless they have a vertical support to support it...When they
get above the surroundings, is when their chance of a strike
goes up sharply. Even horizontal metal can be a problem if
it's really high...IE: beams, etc..MK