I just found a great answer to the problems all in one place in QST, September 2019. The author addresses the same problems in the question, and explains his fixes for a similar bridge-circuit-based Arduino analyzer originally published in QST, November 2017. Also this forum post lists the same problems and planned fixes, so it looks like the answer is that ...
Location and Height
The manual seems to suggest that it would be better mounted outside on a mast.
The manual (page 14) implies that no separate ground wire is necessary.
An Isotron antenna generally should not have any type of choke balun at the feedpoint, even though the feedline carries some common-mode current (and ...
CW 4ever. On 80 Meters, not much difference between 15 or 20 feet AGL. The resulting near-vertical radiation would be good for communications around your region. Experience will show beyond what distance the antenna can't reach.
When you're done with net business, you can get a couple of thousand additional miles by going on 7 MHz and up.
My first ...
If adding an inductive load half way up each leg of a dipole “lengthens” it, I might try the opposite to “shorten” it. Add a capacitive non-hat part way (half?) up each leg. This might partially shield the tips of the dipole, and make them seem shorter. Vary the size of the non-hat to vary the effect.
An antenna which is electrically long at the desired frequency usually presents inductive series reactance at the feedpoint. This inductive reactance can be compensated by adding series capacitive reactance - a single capacitor - between the feedline and the antenna at the feedpoint. This will probably be a relatively narrow-band solution.
Be sure to use a ...
The average power rating is determined by overheating of the centre
contact and is a function of frequency, as heating depends on the
resistive insertion loss. Typical makers curves for a new clean
connector with a perfect load such as page 275 of  for example
imply ~5000 watts at 20 MHz and ~500watts at 2 GHz, i.e. a square root