For years I used a Bryson-esque technique (feet exactly one putter head apart, backswing putter face exactly to outside of trail shoe) as a calibration on strange greens. Compare distance to my “stock” putt distance at my home course. After that calibration, it’s all feel.
To my mind, the perfect putting drill is the Cameron McCormick 3-point drill. It’s got everything! Speed, line, pressure and green reading. Here’s how I do it:
Place a tee two feet from a hole. Pace off about 10’ and drop two ball markers (dimes work great). Pace off another 10’ and place another tee and one ball. One ball forces me thru my entire putting process. I go thru my standard green-reading process. I determine where the line of the putt should pass the dimes. I then position the dimes one putter head apart, straddling the imagined line. They become the “gate”.
Go thru routine, stroke the putt. If the ball rolls thru the dime gate-one point. If ball is between front edge of hole and 2-foot back tee-one more point. If putt is holed-one more point. If putt is short or beyond back tee-no points. Maximum 3 points per (thus the name). If needed, adjust the gate location for proper break. Repeat for 5 putts, record score and number of gate moves. Then change direction, distance and repeat.
If I miss the gate, I need to work on my line and/or face alignment. If I consistently miss low or need frequent gate adjustments, I’ll focus on improving my green reading. Since the total putt is 20-40’ I’m getting lots of speed practice. Because I’m keeping score, there’s pressure. Since I’m recording scores, I can see improvement. Which makes me want to do the drill more.
It is no longer a shock to have a 3-putt free round.
Hope this helps!