HI Sawyer,

Whenever I go out to fiddle with new putters (just to see whats out there) I can usually tell if it has the right toe flow just by the take away alone. Same goes for my own putter. If my take away is bad with my practice stroke, I know I need to adjust my setup, which usually means closing my shoulders more.

Anyway, technology wise I think all you need is a ball liner, sharpie, lead tape, a reliably flat putting surface, and maybe a high speed camera like one on a current gen smart phone. I think you just have to know how to use them and what you are looking for.

Tech is hard to come by for putter fittings. I primarily use our 4 camera system to study launch conditions with a Scotty Cameron crosshair ball.  It helps us visualize launch and spin.  Basically you want a knuckle ball for several frames after impact... but there are many great putters that putt a little draw or fade on the ball.  

Contrary to some of the techie's out there, there really isn't a systematic or quantifiable way to determine the best toe flow design for a player.  Some players with too much arc can benefit from less toe flow.  But some players with toe much arc may not like the feel.... and therefore have less confidence.  Conversely, a player that has too little arc may benefit from a design with more toe flow, but may not like the "swinging gate" feel and feel less confidence.

It always comes down to confidence.  

We are pretty lucky to work with Sneds, DJ, Koepka, Fowler, Walker who are all great putters with different strokes. I used to work for Crenshaw.  We used to work with Freddie J.  Totally different styles.  But one thing they share is confidence in their putting and a few posture cues we work on with players.

First concept in a putter fitting is to lock in the length and lie.  These two factors have the most impact on path and solid strikes.  Then you can fine tune loft, alignment preferences, shape preferences and toe flow.  

One thing I do know is that the Squareback is the most popular fitted putter amongst prominent fitting centers.  ;)

Well put Ryan. I completely agree.

I especially like the part about having different toe flow that than mechanics might prescribe. I've used an eye line mirror and it recommended a heavy toe flow, but feel wise I much prefer a medium toe flow. I wonder if maybe the slight resistance in the arc helps to feel the putter head, similar to having a higher swing weight.