shooting up on the wall or ceiling, you cum have to travel against the gravity. So, if anyone can hit the ceiling from bed, I think you might be over 4 meters on the floor from standing. The reason I ask because the force of my cum on a good day can tricker my partner another orgasm! And I think not many people here recognize this factor.
Many of my friend these days can only make drops just right after their penis heads. And those guys cannot get it rock-hard either. So, I think the stiffness of your penis is somewhat realated to the cum-shooting muscle. I was much stiffer when I was a lot younger and shot that record.