Upload & Sell: On
I do this with the .psd or jpeg files I make in CS5. I then use bridge to create the PDF files, quality is excellent, and the size I want. If you're still struggling with this then drop me a message and I may be able to help (I have little experience with this btw, but what I do is very straight forward).
EDIT: What are you calling massively huge? For example, I have a 12 page PDF, which is 1600px on the longest, at 72ppi, quality 85%. It's around 5MB, which is fine for me.