Top/bottom roller shooter vs. bottom roller only

[jvriezen]

We have been heading toward a shooter that has spinning wheels on both the bottom and top side of the ball. By setting the speeds differently, we can get a desired amount of backspin.

But I'm thinking that in addition to backspin influences, this will also influence angle of exit from the apparatus. I know some designs have only a bottom spinning wheel and use a non-moving hood on the top side (except for possibly angle adjustment) I'm thinking this will result in a more reliable, consistent shot, even though it may not go as far, and the backspin RPMs will increase along with the velocity, vs. being able to independently control speed and backspin with wheels top & bottom.

Thoughts?