I am been trying out some stuff too.
impact miniact casing was glued dead, as the warranty is void if opened.

anyway, knowing some very basic electronics, I removed the limiting resistor to the IR LED, and tried with a 50k ohm pot. resistor.
And found out that somewhere around 15.5k ohm, the range of the IR emission is reduced to a minimum of 3~5 inch.
which means, it can now be adjusted for the "power" of the main gun.

but, from the finding, the pot. resistor value is not directly proportional to the energy of the IR emission. More like exponential.