Exercise that works for me
Natep
Here is an exercise that I taught myself .I do it at home a lot using a driving range mat in my basement .Since you are an upright swinger and use a full sweep release as I do , I think this should help you.
First I hear and read a lot about mid body hands vs impact hands at address. My thinking is that if the best golfer in history (who swung upright and used a full sweep release)used impact hands at address then there must be a damn good reason for it. I read his book "Golf My Way " and he promotes the "feel" of having the club shaft and left arm in a straight line(his way of saying impact hands). This actually makes more sense later on when he talks about taking the club away with his left shoulder and arm as a unit. If you try taking the club away with your left shoulder and arm as a unit(right arm does nothing except support the club as the left arm and shoulder take the club back) it is much more comfortable to do this from impact hands position then from mid body hands position. (try it and feel the difference).
So from impact hand position I take the club back with my left shoulder and arm as a unit and strive to make a nice shoulder turn and at the top of the back swing I load (let the weight of the club come to rest) on the #3PP.Pause (in the real swing you would not pause..you would immediately transition into the downswing..but for now pause to get the feeling of the weight of the club on the #3PP)...feel the weight of the club on #3pp...then smoothly shift your weight and at the same time concentrate on MAINTAINING that pressure on the number #3PP down and through your aiming point (I use a sponge golf ball at home as my ball and place a penny 4 inches in front of and slightly outside the plane line .This penny is my aiming point for irons,and i forget about the ball.) and maintain that pressure as far as possible into the follow through. Do this in slow motion first,,,then as you get the feel you can start to speed up the swing until you get to full speed. Full speed does not mean herky jerky...You should always be smooth, deliberate and heavy.NEVER jerky or spastic.
One final point,,, Once I get to the top of the swing and the club weight has been loaded onto the #3PP my brain totally forgets about the club shaft and clubhead. The only thing my brain cares about is maintaining that #3PP point and AIMING it (yes aiming the #3pp NOT the club head or shaft) DOWN AND THROUGH the aiming point and maintaining that pressure through the follow through and into the finish. As you get more confident you can become MORE deliberate and heavy but remember NEVER herky jerky...that's hacking.