Page placement using blowup package

Question

I am trying to rescale a book which has the dimensions 152x229 mm set with the geometry package into 165x242mm using the blowup package. After some messing around I have managed to get it to rescale by giving the paramater noscale. (what's up with that btw, without noscale it doesn't rescale at all and if I give noscale it does rescale -- I really expected the opposite behavior...) However I can only get either my right hand side or my left hand side pages to be correctly placed. If I use this command:

\blowUp{paper={165mm,242mm}, noscale, pos={left, inside, top}}

my right hand side pages look good, and if I give this command:

\blowUp{paper={165mm,242mm}, noscale, pos={left, outside, top}}

my left hand side pages look good. In both situations the page not looking good is set about half a page to far to the left. I have come up with this solution by trial and error. If I don't give any pos at all the pages are set with just one little corner inside the printed area. Does someone know how this can be fixed and if not then perhaps at least someone knows what these paramaters actually mean. Especially the inside and outside ones feels a bit like magic to me. The documentation only says they exist but not really what they do... :(

Answer 1

Right I now have an answer to my first part of my question. As in how can I make it work. Further experimenting has made me realize this combination works:

\blowUp{paper={165mm,242mm}, noscale, pos={top, left}}

I thought I had tried that combination already when I asked the question but apparently not so. (It's a rather obvious combination now that I think of it...) I am still at a total loss at to what does parameters actually mean though...