The mod:

I repositioned the right hand "antenna" tuning cap. to make room for an isolation shaft coupling. The kind meant for work like this. Sure, the cap's shaft has plastic insulation on it but it still had a fair amount of capacitive coupling to the metal set screw and skirt of the knob. Enough to get RF burns. But with the now double insulation with the isolation coupling and a non-conducting phenolic rod, this capacitence is way lower. Less than a pF. No more burns or RF interaction of my hand when tuning. Used a metal bracket that was used to mount an adjustment pot inside an old Tektronix scope, to mount the cap. This bracket becomes RF hot, as it touches the tuning shaft mount. Used plastic screws, nuts and a piece of glass epoxy circuit board to isolate it from the chassis. Had to reposition the inductor to make room for the repositioned tuning cap. Drilled new holes for the inductor ground connections. Also remounted the inductor selector switch to get a little more lead length to the inductor taps. Just be careful you keep about 1/8 inch between various metal parts that carry RF, like terminals. Be sure you can turn the knob back and forth freely, that the tuning fins don't touch anything, including the inductor or that lead to the top of the inductor.

Now your hand should not influence the antenna tuning. And not get any more shocks or burns. You may find that some of the lower frequency bands tune differently, but I got them to tune into the same 40m dipole I used before with different inductor selections.