RE: Heavy verses medium classification.
Panther G, the Pershing had absolutely no stabilization at all other than the gunner's left hand on the elevating handwheel and right hand on the power traverse handle. There was no power elevation/depression on the Pershing's gun as it was totally manual. This was the same on the M-46 and also the M-41....elevation/depression was totally manual and no stabilizer can be made to work on a manual mechanism. The first tank to have totally powered control of the gun was the M-47, all hydraulic and very noisy.
Firing on the move, even at slow speed was extremely questionable, as the vibration from the tracks made the gunner's sights jiggle and vibrate, that you could not put the crosshair on the target. At best was to keep the tank at a steady speed around 5-8 mph where the vibrations would level off a bit, aim low and fire. At the angle and short range the Pershing fired on the Panther, it was a good choice and a lucky shot. Russian T-34s were prone to fire on the move, but this was Russian doctrine scare tactic and rarely got a hit.