do yourself a favor and open up 3 or 4 bales of hay and just throw them into the baler while you run it at full speed.
Trying to do it by hand is an exercise in futility. Yes, it's a good way to catch an obvious timing problem, but when it comes to issues like you're having, the knotters are going to work differently at speed an under tension. Best to adjust and test under real world conditions.
Only "trick" is to kick the knotters early - make half sized bales so you don't have to wait forever.
It'll take at least three bales, four or five would be better. You'll lose a lot on the ground, and you'll probably be at it for MANY cycles, the hay keeps getting crunched and mutilated - so you need a lot of extra to consistently churn out test bale after test bale.