Looks good.

That is a good technique to learn putting holes in curved surfaces and keeping the edges tight comes up a lot and having a technique that can produce consistent results should come in handy.

I have seen a lot of tutorials where they just create really dense meshes for both the surface to be cut and the cutting surface and boolean them together which creates really messy geometry that cannot be smoothed.

I hope the tutorial got across some of the key things that will make using booleans more comfortable and rewarding.

The big take aways should be.

- Try to think about the geometry you are going to boolean so that the cleanup is not to difficult. For instance cutting through a 4-sided face use 4-sided geometry, cutting through two 4-sided faces then use 6-sided geometry, etc.

- Make some simple tests. As in the tutorial starting with the 8-sided cylinder and then trying the 16-sided to maintain the curvature.

- Take advantage of symmetry as much as possible.