[Elecraft] Best Way to Make a 1/4-Wave Reference Wire?

[CRAIG W BEHRENS]

I'm fooling around with custom portable Vertical array antennas for portable and DXpedition use.
I was wondering if anyone in our list Brain trust had a favorite way to cut wires to a (reasonably precise) 1/4-wave length. 
(Yes, I can measure and No I don't want to model, I want to field test and calibrate.)
What I want to do is have an elevated vertical (say base at 8'-10'), and add a temporary 1/4-wave "reference" counterpoise wire with a 20-degree downward slope.
Then, use this set-up to adjust whatever physical items I'm using for the vertical element to get a 1:1 match, calibrated to the radials length.
I want to end-up with a balanced antenna that is resonant and does not require a tuner (given that I'll have some minor adjustments to fine-tune the antenna's match at different locations).
So, theoretically, the vertical could be made of 6-inch diameter aluminum tubing (not likely in the field), insulated or non-insulated wire of any size, or whatever.
I'm also curious about and I to be able to see what the differences are in the lengths of antennas based on what materials of different types and sizes that I use.
Ideas???
Thanks.

72/73,
Craig W. Behrens--NM4TK3, KX3, K2, K1 +++