Respects Ron Boss
The subject interests me too. And I find your transition between short duration and long duration wind design very fascinating. You should let us know more on the subject. I have carried out steel tower designs in collaboration with some university professors who always force me to do conservative wind design with large pressure coefficients. To discourage this behavior I ended up using TIA-EIA-222-F, which is used in transmission tower designs. The towers even with this code would undergo large wind drift. And I would be told to take only 70% of this as design drift since the winds I have used would be very short lived.
By the way, Carlbauer, next to Ron's comment let me add. Unless you have too much time to spare, make a discovery that 30m height is relatively a reasonable height and unless your design specification suggest a rigorous analysis, I suggest you follow codes like TIA-EIA-222-F(US) and ASCE 7 (US) or CP3(UK) or DIN 1055(German).
What is the purpose of your tower? Is there any cladding. For a 30m tower to acquire a 0.8m seems to me that you have a serious vertical loading. If that is true then are you in seismic zones?. If yes, then unless you have more than 120kg/m2 of wind over there, then you probably have to do dynamic analysis, not for wind though but for quake.
Ron, please comment on your great duration-basis approach.
Respects
IJR