Looking good so far, Boni. What version of Blender are you using here? I forgot to mention I was using 2.83 in my example, so the hotkeys may be different than the version you are using. CTRL+R was the hotkey for creating loop cuts, but I see you've already got that done. I would recommend staying away from booleans if you can unless there's truly no way around it. I think using a sphere as you have done in your example above is probably the most acceptable way to go. If the pole at the top becomes a problem for texturing, then there is a way to do this using a cube but I don't think it should be an issue. Let me know if you have any problems with it. I could show you a relatively simple technique to transform the standard cube into a band shell as well.

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