I changed out the poor fitting plastic nose cones for balsa cones. Balsa was used on the early versions of the Centuri Mach 10 kit.
The tank tube holds some glide trimming clay. To make more room in the tube, some of the nose cone shoulder was cut off.
The front nose cone is glued in place. The rear nose cone is left loose so you can take it off to adjust the clay weight.
A brown coupler is glued into the front of the BT-60 tube to strengthen it and add some weight.
The coupler was too tight and had to be sanded for a slip fit.