"The clouds on Venus are formed continually out of SO2 and H2O reacting and making H2SO4, which then drifts down into the heat and is decomposed back into the gases. Thus the 30 km basement of the clouds - that's the level the vapour gets cool enough to form the droplets out of the component gases. No rain ever hits the ground as the droplets evaporate and the sulfuric acid is broken down before it gets close. Maxwell Montes is still too hot by about 35 degrees for sulfuric acid to be stable."

Interesting.
So, there is a temperature and pressure point in which H2SO4
decomposes?
Would the night side have a different elevation than day side?

Is there anything that prevents SO2 and/or H2O from being in lower elevation- other than they have slightly lower specific gravity

"As for air columns sunlight has to travel through a lot of air when it's near the horizon, so that might make for a fair comparison."

Yes but if you looking from say below 10,000' the horizon isn't very far. If you have a tall mountain below the horizon you could see further. Such objects at such distance does appear hazy, but dust could major factor in this regard. And in any case you simply aren't going to see as far as 1/2 of this distance [430 km].

From Space one could see such distance and one get some idea of it- assuming you used a telescope or binoculars. But much of such distance would going thru vacuum of space or less than 1 atm of atmosphere. So the point might be somewhere around 800 km away and about 1/2 to 3/4 of the distance being somewhere close to 1 atm "worth" of earth's atmosphere. And similar thing would be a lunar ellipse and moon turn reddish from earth's atmosphere