Buffer time
Each time the robot arm is lowered by default, it starts to grab quickly, which causes the objects to be thrown far away and needs to be picked up manually
At present, my solution: first put the manipulator in the open area, adjust the distance by F key, copy and paste, and put the solid manipulator.
Can a buffer time be made. When the manipulator is put down, the manipulator does not work immediately and starts to work after a few seconds. In this way, there will be a buffer time to put the receiver or adjust the distance of the manipulator, so as not to throw something to the ground.

Normal inserters do not have a buffer delay like that so I think it would be weird for throwers to have that. I think it is more intuitive to either power the throwers after you set the right distance, or route the items to the thrower after you set the right distance. The copy paste method you described works too

Turns out it is possible to have adjusted thrower range in blueprints. New version lets you adjust thrower range before you place it