Great choice! And a good idea (using the short length for a payload bay).
To answer your question... I'd wrap enough tape around the shoulder to hold it in place. You could tether it with a short length of shock cord, but tape is easier . A third option would be to use a clear tape to physically tape the nosecone to the payload bay, but there's always the risk of peeling up paint with that. Gluing it down and it's now a sealed tube (great for buoyancy if it goes for a swim).
The key thing is how much weight are you going to put up there, and how free is its movement? A payload that is heavy and loose, and the shock of the ejection could knock the nosecone off. Light and secure, and friction fit should work fine. If you're worried about pressure differentials popping it off, you can always hide a small vent hole in one of the black bands of the wraps, and rotate that to keep it oriented away from the pretty side for photos.
View attachment 418621
If it helps,
you can download my sim (with the zipperless mod) and use that to help you figure your motor options w/and w/o a payload. If you want to try to match the image (above) my markings on the sim are set up at a ratio of 1 pixel = 1/100". So 1/8" = 13 pixels (you can't do a 1/2 pixel). Basically the bottom of the large wrap is at the bottom of the payload bay, the narrow wrap is centered between the top of the tube and the top of the large wrap.
