I think you're going from under-kill to over-kill, maybe.
I've seen your questions on this and a couple of other threads, so I hope the replies don't come back too fractured. It's best to start a new topic this way instead of getting an old topic to diverge.
The HDBX tower is the Rohn "heavy-duty" BX self-supporting tower, but it is only designed for antennas and other "flat-plate" loads. The wind can do nasty things to antennas, and they get loaded up with ice in certain places, and civil engineers are used to working with those parameters. The trouble you have is that a wind turbine doesn't only apply a wind load, it applies other mechanical loads to the tower, of a kind that are not considered in the typical "antenna" analysis.
Three main types of load:
1- Weight
2- Thrust
3- Gyroscopic
Every time that rotor changes direction, it wants to pitch up or down, due to the gyroscopic motion effect. Try it with a bicycle wheel (if you didn't in school or have never heard of this).
If there is modest turbulence on your site, the gyroscopic loads could cause as much stress on the tower as the weight and thrust loads do.
A Rohn HDBX is actually almost good enough for all of these loads, but IMHO you must modify it to have a reasonable safety factor. There must be at least 3 guy wires near the top to reduce the bending due to thrust to a level that the bending due to gyroscopic torque and weight (column buckling/crippling) cause it to fail. I've see people skip the guys and put turbines on them anyway, but there's no guarantee that it will last for a long time.
The very POINT of having a wind turbine where it is, is to capture energy from STRONG wind. Exposing a machine to that condition requires safety factors and confidence.
Depending on your site, you may need even more reinforcement than that. The only way to know is to find out!
