well, i dont look on Venus colonization deep to say the truth.
But, how they get many tonne´s weigh of their "cloud baloon" to the atmosfere?
I mean, on paper it looks nice, but hey, you must get it there in one rocket. Let say it could weigh 20-30 tonnes itself + 20 tonnes of supplyes for humans on board.
Have we something what can get 40-50 tonnes into venus atmosfere, release it there and return to Earth?
And that is realy possitive approximation of weight.
And, if we think about long-time colonyzation, we need baloon resuplation.
I can´t even imagine somethink like that in atmosfere...
I heard about project with mirrors between sun and Venus that could in long time period cool tempeture of Venus, but that is still only on paper. - Theoreticly possible, practicly impossible, now. Sorry, I don´t remember name of that project...
And sorry for totaly offtoppic.