At AGHR we did a board around @gunrunnerjohn's booster that takes this effect into account. We operate in closed loop and have a microcontroller tweak a digital trimpot feeding the booster. The microcontroller senses voltage on a strip of metal nearby to the layout via some mini-circuits amp and an envelope detector.
Adrian - Can you talk more about the benefits of the added elements you add to the GRJ booster. What improvements did it add to running TMCC engines?