Greg,
There's the official way and then there's the practical way.
If it is already up, that carries a lot of weight in your decision. Being wireless, its easy to move, but time on the tower is hard on my feet and having a ground crew is sometimes hard to get in place.
I think the most telling tale is you saying you had almost constant breezes or zephyrs depending upon the day.
The natural mixing and movement is going to cancel out any stratification that may occur otherwise. The guidelines say wind at 30' up or so, and there are a lot of papers from universities showing the wind speed slowing caused by the earth's surface, and this makes sense, but it is tough to get something that high, not whip around, and yet be able to be 'easily' taken down. Haven't been able to find a sky hook at at flea markets lately.
I think the height above ground was chosen for, well, the observer's height. I recall being envious of the white slatted shelters that we'd see at ranger stations or DNR offices, all on stilts which my dad joked was to make it hard for snakes to curl up inside them.
I'll look to see if there are the same kind of graphs for variation in temperature with height the same as the wind speed ones that I mentioned. But standards ARE standards and if you go too far from the expected, there is going to be avoidable variation. I know that of the many thermometers and humidity sensors I have, some are differing by a couple degrees and 20% depending on sun, wind, how much vegetation is growing, whether it rained and the underlying leaves are soaked, and so on. Wind is a great equilibrator, mixing things up a lot.
I'd probably not go to too much trouble, but the little battery may need changing once in awhile, but you have a good safety harness for climbing. And I don't see many maple or oak trees for plugging up the rain collector as much as my woods does.