For smaller scopes, I like to make octagonal tubes. They remove the need for a tube box and locate the eyepiece at the right angle and have a flat area at the top for a handle and a finder. I’ve made several of these tubes. I cut the pieces from 6 to 7 mm plywood on my table saw then add a 22.5 degree bevel on each of the long edges. You can add the bevel with a router and a 22.5 degree bevel bit if you prefer.
Here is PDF version of a presentation I did showing how I assemble the tube:
https://drive.google.com/file/d/13LG...w?usp=drivesdk
Here is a short video showing the assembly:
https://drive.google.com/file/d/1WGM...w?usp=drivesdk
Below is the completed tube next to an 8 inch F6.