IMO, the biggest problem is caused by putting the bow on the tiller supported in the wrong place and pulling the string back in the wrong place.
Try to feel exactly where your hand will support the bow (usually about 1" below the arrow pass unless you use the heel of you hand a lot)
Once you can get a proper length string on somewhere near brace height put a bit of tape on the string where the arrow will be nocked and draw the string back from just below that point.
This way the tiller is simulating how you shoot and you will avoid a nasty shock when you see the bow being used.
The other point is don't clamp the bow on the tiller allow it rock back and forth as it is drawn.
If you do it as I suggest you will see at very low draws the bow is skewed, but this is how it looks in reality when you hold a bow! As you draw it all evens out if the tiller is good.
Del
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