I tried adjusting the ball detent pressure using the screw, but it is very "touchy". There is a point where if the screw is too tight, it is very hard to get the handle to lock in place and to unlock to charge the gun.

If you back off the screw just a little bit, it gets very easy to snap the handle into the detent position. But in this position, after the last round in the mag is fired and the bolt locks open, I have notice the handle is not locked forward and is just "floating". When there are still rounds in the mag, obviously the handle is held forward by the closed bolt. 

It seems like recoil bouncing the charging handle out of the detent position. It essentially defeats the purpose of having it "non-reciprocating". 

I wonder if maybe I need to use a different weight spring and a shorter screw for the ball detent to give it a little more adjustment range.  I think that the spring might be very close to being fully compressed with all the coils touching so the ball detent doesn't have any travel when you try to increase the tension.

Any thoughts or experiences with this? This is a brand new upper 

In for the answer....I just got a stripped side charger upper w/LRBHO from them today...

I was delivered an NFA side charge LRBHO stripped upper Friday, assembled the barrel (16", 9 mm, Spinta Precision) to it yesterday and mounted the mostly assembled upper to the previously purchased and assembled PSA badged, NFA Glock mag lower; but have not tried shooting it cause I need to get a riser for the front sight I'm using.  So my answer is based on an, as of yet unfired setup.  Having read the above posts, I have cocked and released the charge handle 500+ times without any adjustment to the detent spring tension.  That has smoothed down both sides of the ridge that the truncated ovoidal detent rides over to unlatch and latch.  Then I oiled the ramp area of the upper and dribbled a couple drops of oil onto the detent. Now, both cocking and forward latching seem smoother with less effort, and still remain positive.

To make the multiple cocking actions more effortless, I took an AR-15 A2 type grip, held it in the normal position, put the open bottom over the cocking handle of the upper, and pulled rearward then let the recoil spring return the bolt forward.

Best of luck with whatever you decide to pursue, and enjoy many good times with your upper.

MHO, YMMV, etc.

I took it back out to the range today to run a couple of mags through it and after tightening the detent screw very slightly over the stock position, it seems to have fixed this issue. I am seeing pierced primers, but that is totally unrelated. The charging handle appears to be working as intended.