"....rule of thumb.."?? Probably not, but let me ask you a personal question. You and I start the round with those clubhead speeds, but can you sustain them throughout the round as you fatigue carrying/pushing/pulling your clubs? ... I can't!!!
Oddly enough, when I ride the course, my score goes up ...!!!!

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Okay... here's another thought. Most recreational golfers experience what is called "distance compression" as they go from short to long clubs. What happens is the distance between clubs decreases as you go from wedges to driver. Typically the 'compression' takes hold in the fairway and driver clubs where you get the same distance for your driver and 3-wood. Clubhead speed and impact efficiency becomes factors as the shafts lengthen.
Do you experience "distance compression" towards your longer clubs?