How much disk space do I need to install PTS? got 35g now, won't work atm
That's about (very roughly) the size the initial download was for me when I downloaded PTS late last week. It has been stated that the patch to 1.6 will be around 14gig, so I would say you'd likely want to double the amount of free space you have (from the 35gig you mentioned) in order to give yourself some wiggle room. And if 35gig is ALL the free space you have on your machine... well, it might be better to go with even more free space than that before attempting to download it.
At the moment, the last version of PTS is using 35 GB in my HDD. Sum this with the new 16 GB patch. So I believe you wont be able to access PTS with such limited hard disk space.