Layered PSD file to multi page PDF ?

I am trying to take a layered PSD file, and turn it into a multi-page PDF, with each of those layers beoming its own page. 

I have been successful in exporting into - seperate PDF pages - and even this is alright, becuase it is then pretty easy for me to gather those up and - Combine Pages into PDF, etc.

However the problem here - is that the PDF's that are being exported ( the individual pages ) are huge.

They are coming in at like 4 or 5 Mb., and I don;t seem to have any options for controlling size / quality, etc. 

Therefore - How do I keep layer pages that are only like 1800 x 1200 pixels ( which should in theory be happy at 500Kb, etc - from becoming these giant files, or better still - how do I simply export them into the single PDF I will eventually need ? 

( when I typically will save something from Photoshop to a PDF, I get all manner of options - Layers, save for Web quailty, compression, etc. when I do this 

FILE - SCRIPTS - EXPORT LAYERS TO FILES, it works well - fast etc., but again,   individual files are then too big to be of use ) 

Thanks for any help or guidance,

Sterne