Hej Matt,
I must admit I stopped reading the thread after Andrew VK1DA’s posts to which I absolutely agree. Maybe you want to know what vertical I use and which I used for our portable-2-portable QSO on 20th April.
I designed her for the 2015 SOTA 10 m challenge when I wanted some DX’ish antenna for that band. She’s basically a 5/8 lambda radiator over three counterpoises which I usually feed at roughly 2 m above ground level. All counterpoises slope down to 1.4 m which is the maximum length of my walking poles. 
So I took a piece of antenna wire (6.2 m) and also made a loading coil for 10 m resonance.
A simple L-match makes the antenna multiband 14, 18, 21, 28 MHz. 24 MHz would be close to halfwave resonance, so it obviously does not work there. Each counterpoise has a link to vary their lengths. A current choke / 1:1 balun is needed at the feedpoint, e.g. ferrite core of mat 43.
I close the coil switch for operation on 14 and 18 MHz, on 21 and 28 the switch stays open.
Don’t ask me which counterpoise length I use on each band, I just can’t remember. If I can’t tune her, I just open/close all links. I was always able to tune, regardless of the summit I was on.
I also tried to make the antenna work on 7 MHz, which needed an additional loading coil (a larger coil with another switch didn’t fit in the small housing) and another switch which connects the capacitor either before or after the loading coil. It seemed to work which means I was able to tune the antenna and I had some QSOs on 40 m. But the linked dipole performed better for inter-euro QSOs and 40 m would not be the band of my choice for SOTA DX. So I abandoned the plan to use her on 7 MHz on a regular basis.
Ahoi
Pom