Hi, I decided I wanted the option of installing 5 motors (1x 24mm and 4x 18mm) in my Estes Saturn V #1969, so I built this: The centering rings are 2.3 mm and 1.5 mm basswood I cut and drilled, and the red electrical tape is just my cheap way of attaching the motor hooks. I alternately used both epoxy and wood glue for no particular reason. My concern now is how deep should this be recessed in the BT-101 tube. Too deep and I suppose the outer motors could char the tube. Any other thoughts you might have before I glue this in are welcome, thanks.