How long should I wait before driving from sea level to 8000+ft after a pneumothorax? I have had vats pleurodesis before but had small recurrent pnemo

Depends. On the remaining size and number of blebs or bullae. If on the cat scan of the thorax none are left and a good abrassive and light talc pleurodesis was done the chances of a recurrent spontaneous pneumothorax is less than 1%.
Depends. The answer depends upon the specifics of your situation- why you developed a pneumothorax (spontanious, tramatic, underlying lung disease, etc), is it recurrant, and how much is still left. The doctor who is treating you can best answer this question.