Alan,
Nice work! The 3D model will look great.
When I designed the Korber version, the limitation of laser cutting was basically 2d parts. So the Korber tower does follow prototypes that do exist, but ar not the most common. Th3 use of 2d parts took me to using a 4 sided prototype so the joints at the corners looked right. The bracing you refers as X is really a Z brace, you will find these are protypical of towers made by Rohn, specifically a Rohn 45G for example.
Also the tapered base sections are designed for self supporting towers, it is rare that these are also guyed. If you want to guy a tower you would typically use a uniform cross section tower with no taper. The issue is you would need approximately 70% of the height as the distance to the guy anchors, so on a model rr it would be a lot of space.
Again very nice work on the 3D model.
