DW calls it The Infinite (Slotted) Stroke Adjustment to vary the distance the beater travels before hitting the drum. For a slightly longer stroke move the screw towards the back, for a shorter stroke move the screw forwards. It's the distance between beater and head that this adjusts.
But the spring is still engaged. Adjust your rocker angle - distance beater travels before hitting the drum - does not determine where in the stroke the spring engages. It's engaged all the time.
No that does not determine where spring tension is engaged. It's engaged all the time.
That adjust beater angle. Doesn't do anything to spring tension or where spring tension is engaged.
Check out this video. It shows that as adjustment for beater angle. I have same pedal. It adjusts beater angle.
https://www.youtube.com/watch?v=7TrGp6dF9ZA
DW calls it The Infinite (Slotted) Stroke Adjustment to vary the distance the beater travels before hitting the drum. For a slightly longer stroke move the screw towards the back, for a shorter stroke move the screw forwards. It's the distance between beater and head that this adjusts.
But the spring is still engaged. Adjusting distance beater travels before hitting the drum (what DW calls it) does not determine where in the stroke the spring engages. It's engaged all the time.
'If' you have your spring engaged 'all the time' so to speak, which means there's a slight bit of tension on the spring with the pedal at rest, then the the adjustable rocker screw will alway be at 180 degrees (6: O'Clock). Where you put that screw on the rocker does determine beater angle, but again that's only if you have constant tension on your spring.
I don't want to fight a BD pedal spring from the get go, it's pointless and a waste of energy, and it makes it more difficult to play the pedal as you're always adjusting your foot/stroke to constant spring tension which is crazy IMO.
What determines the the rocker screw position to beater angle is actually spring tension, if the spring is loose (no tension at the beginning of the stroke) the rocker screw will position itself away (clockwise-up/towards the bass drum head) from the 6: O'Clock (180 degree) position until it engages the spring.
Most drummers have + tension on the their springs with the pedal at rest, and just because they never thought about it, that's the way the pedal came, rocker at 180 degrees, spring loaded, tension as soon as you depress the foot board, its not at all an efficient way to play a BD pedal tho.
If the BD pedal springs job is to return the beater (and it is), why would you want tension on he footboard all the time? Makes no sense. You fighting from the word 'Go', a waste of energy. The most efficient use of energy comes when a pedal's spring is set to engage late in the stroke, close to impact, the only place the spring is really needed. Why tension your foot at the beginning of the stroke?
Spring tension on a BD pedal is not linear, its compounded, the deeper you get into the stroke, the more tension the spring experts on your foot.
The biggest problem with beginning drummers on the BD pedal is their inability to overcome 'constant' spring tension, its actually a backwards way to developing a good pedal technique.
You only need spring tension to return your beater, not create resistance at the beginning of the stroke, that's energy working against you.