It really depends upon why they're a 15 handicap. A high swing speed is basically all you need to back up the ball. If they can make a 56 degree wedge hiss aggressively, they can probably back it up on firm greens. There are many 15 handicaps who can swing really fast, but hit lots of trees on the way to the green.
Sure, this is true. Even instructors who've been "doing it for years" and "seen 100,000s of thousands of golfers" can make be mistaken about someone's ability.
The problem is no one knows what's going on "in your swing" except yourself. Even then, may of us don't know.
The 300 yard 20 capper example you gave is not unrealistic. An old instructor who fit many clubs over half a century told me that the average male should be able to get 105mph swing speed. He based this on understanding mechanics and seeing people's swings are not even close to optimal. He's a TGM advocate, but seems to know his stuff. On the internet could sound just like a 76 year old kooky golfer, but in real life he makes a lot of sense.
I'm not very good. With that being said, my yardage gaps are consistent (10-15yds) all the way through my bag so fairway shots >95 yards are always full shots for me. I practice <95yd shots on the range regularly, so I am capable of rolling a 3/4 swing out across my bag.
Now, I'm not very good (remember?). With that being said, I am in trouble frequently off the tee and I have to focus on less-than-full swings regularly to get the ball back in play. Off-fairway/slight trouble, my go-to play is a 6i since i can keep it low (read: under a tree) and can control distance "pretty well" anywhere from 100-150yds, typically staying within 20 yards of intended target. Sometimes this is more of a punch shot, other times I am trying to draw it around trees (mostly unsuccessfully). But - If I am my full 6i distance though, I am hitting a full 6.
The biggest problem I have is instead of taking a 3/4 full swing, I have the tendency to decelerate leading me to hit about 24" behind the ball - this is why I typically opt in for full swings when I can. Purely Mental...
Maybe I'll get on the range and try this "flighting" technique a bit more
not all that unusual design. It is older but, I remember seeing similar about twenty years ago that looked to have been CNC Milled, cylindrical, but not with end caps. The head also did not have a flat face. The idea was to impart top spin. You would hit just like any putter, not like a croquet mallet. Not sure of the legality, but if I were to design something like that, I would have the ends as wheels and use a push stroke as in shuffle board. Dumb? Maybe, Effective?, probably, Different? definitely.
I did a ball fitting at one of the golf superstores a few years ago and wasn't satisfied. First they asked me what brand of ball I wanted to try, and then it turned out they recommended the most expensive ball of that brand. I would like to be able to start from scratch and have them give me recommendations on different brands and models based on my swing parameters, maybe narrow it down to 3 balls that wont make a difference with which one I pick.