Okay, following is probably Bat-crap crazy, but we'll run it up the flag.
My understanding is you want to drop as much nose weight as possible. Your current configuration is NON-minimum diameter which seems a bit inefficient.
Here's my play:
Minimum diameter tube, longer than yours to accommodate a streamer IN FRONT OF rather than around the motor.
There is a "cut" in the tube, the rear section is mounted to the pylon, the front section is completely loose (we'll get to the attachment in a moment.)
The motor is friction fitted into the front tube, with a significant portion sticking out the back which will slide into the FRONT of the rear tube.
The rear tube has a posterior motor block, although I doubt the motor would kick out. This can easily be made with a 1/8" cut tube, with a segment out. Will recess the motor less than 1/2 diameter to keep away from Uncle Krushnic.
There are two holes in the forward tube which will be just in FRONT of the motor. Using a #8 2.25mm Crochet Hook (doesn't have to be exact, but I find it fits well through a "hole punch" hole and grabs rubber bands well, a rubber band will cross this area to hold both motor in place and hold tube onto back tube.
Not pictured is a forward motor block on the forward tube to perfectly position the motor so just enough sticks out that the rear of the motor will slide into the rear tube exactly to the depth of the rear motor block, so the forward and rear tubes come into contact.
Okay, load up.
Friction fit the motor into the forward tube. If you are insecure about "securing" the motor with friction fit, you can probably add an extra external tape and still be able to slide the rear of the motor in place.
Load the wadding and chute and nose cone into the pod.
Okay, slide the motor into the rear tube.
Now, us the crochet hook to pull a number 16 rubber band through the holes, run both loops around the rear tube. I have attached a video of how I do it for my helis and air brakers.
Now, activation.
Launch rocket.
Ejection fires, it burns the rubber band. The front tube is now loose.
In addition, the nose and chute or streamer are ejected.
Between either the kinetic energy of the nose cone ejection Or the streamer or chute drag, the tube is going to be pulled off the glider.
So there you have it. Minimum diameter, a little longer put likely similar or less weight than planned non-min diameter, and you nearly completely dump not only the nose cone and motor (mount) but most of the tube.
https://www.rocketryforum.com/threads/“tubeless”-video-how-to-motor-mount-rubber-band-helicopter-and-airbrake-recover-method.160118/#post-2014334
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