During the 1960's and before, the golf club fitting process has evolved from watching someone swing a golf club and then hand them another club until all of the available clubs were tried. I then made a recommendation. I did this for many years as this was the only method. At that time, I was considered an expert because I did it so many times. I would assign a probability of success in the (15-30%) range.
Then the TRUE TEMPER SHAFT LAB came into existence in the 1990's, it would show the bend, droop, stiffness and lead-lag of a golf shaft as the club/shaft collided with the golf ball. There were 4 wired clubs (RH 6 Iron and Driver and a LH 6 Iron and Driver) This was the very latest technology and was very cumbersome with all of the wires attached to the club. And the instrument had to be recalibrated after a couple of dozen swings. This process highlighted the golfers swing and I had to guess what shaft and head combination to use. I would again start handing them different shaft/head combinations.
I would assign a probability of success in the (30-50%) range.
In the 2000's, the launch monitor was introduced and I had a $20,000 TrackMan launch monitor. What a great tool for golf club fitters. I had golf shafts and heads that were interchangeable and I could really zero in on what the customer needed. It took a lot of guess work out of the fitting process. I sold my business to California Custom Club in 2013 after many successful years in the club fitting business. I would assign a probability of success in the (60-70%) range.
During those 50 or so years, I was never influenced by the golfers swing. I believe that a golfer has his clubs fitted properly and then find a swing coach.
Did Usan Bolt learn to run the 100 meter yard dash in flip flops? Do the best golfers learn with off the rack cheap sets of golf clubs. NO! They get the best tools available then learn wow to use them and make tool adjustment as they perfect their skill.
Here is how I do it. I concentrated on the moment of impact. It did not matter how the golfers swing gets to the ball but what were the results at impact. During the period of 2003 - 2014, I fitted over 1000 golfers and 100,000 swings. I looked for ball impact, launch angle and reverse ball spin metric's and it got to the point where I could predict distance and angle of decent within a few yards. That's the scientific method it's really helpful for figuring out the tricky things.
A few years ago, Golf Digest (I'm in the top fitters list), provided Tiger's metric's on one of his drives. Ball speed: 185 mph, Launch Angle: 8.8 degrees, Ball Spin: 2200 RPM and Distance of 299.16 yards. I entered this metric's into my equation and came up with 300 yards. I knew I was on to something.
Distance vs spin, distance vs angle of decent and distance vs height are presented in graphical form on my computers. "There's this thing called physics, which is this scientific method that's really quite effective for figuring out the truth."
I can precisely dial in your golf clubs.