In my zeal to make the body frame strong, I ran out of white pipe cleaners. Remember, we are going to cover all this with a layer of felt.
Use the same framing technique on the head as you used on the body.
Reference drawings can be helpful, but only if you measure every now-and-again to make sure you are on target.
Serviceability is a good thing to keep in mind... if something breaks, how hard will it be to fix?
A good example, would be adding a speaker grill if you don't have one - making it much more difficult to puncture the delicate cone.
Use enough hot-glue to mount components securely... somewhere between temporary and permanent.
And... a little more generous on components that vibrate!
Use some more hot-glue to affix the upper neck flange to the head-plate. Glue the 12mm dowel into that flange keeping it perpendicular to the base and centered (roughly) within the neck.
This is my favorite stage of a project, where personality starts to emerge!