Calibre changes the .PDF pages size

[beniof]

Hello! I have posted this thread on E-Book Readers > Sony Reader ; but now
I know that it is a problem with Calibre.
I have bought Sony PRS-300 reader two months ago and still can't use it for reading. I have many large PDFs which contain tables etc.
and I wanted to read them. For sure, it is impossible to read these PDFs as PDFs because changing the pages is very, very slow. I spent a lot of time with different programmes, but only get more frustratied.
What really helped was to convert them to .LRF using Calibre. Despite of the time it takes to convert 6mb file (more than one hour) and that it makes a
6mb to a file 40mb, it works fine. But, the problem is, that the letters were too smal and they can't be resized on the reader.
So, what I decided to do, was to resize pages using Foxit PDF Editor
manually. It took about 0,5 h for every 100 pages. I saved the PDF and everything was fine in an Acrobat Reader. Then I converted it to .LRF using Calibre and send to my reader...the pages were not resized, only the cover... Why? I tried different settings, didn't help. Below you can see how I resized the page.

To conclude: perhaps it is hard to understand what I wrote, but will try to explain it clear. The problem is with converted .LRF file. When I send to my reader the .PDF file which was resized manually using FOXIT PDF EDITOR it is shown as I would like it to be shown: can read it easily. But the problem is that changing the pages is very, very slow. When I convert that resized PDF file to .LRF only the cover is resized, all other pages - not. So it is not a problem with Sony PRS reader.