Hi, Lagi - and welcome to the forums. Access to Beta is not available yet, since I am focusing really hard on getting the Greenlight launched. Once that is done, I will make a Humble
widget on this site as an alternative way to get access to the beta.
I share your fondness for reading about games, including manuals and wikis. Having a physical manual is something I do miss some times, now that almost all games I purchase are from online sources.
So I really like your suggestion to make a pdf that can be printed. To be honest, it's another thing that will have to wait until I am done with my current Greenlight preparation efforts, but I actually find it somewhat relaxing to document mechanics, making tables with unit/spell/upgrade stats, etc.
The documentation part of this forum is currently serving as a draft for the proper documentation, for which a wiki will be the main repository (since a wiki is very suited to linking to from in-game), but I will make sure to add to my build-pipeline an export-to-pdf step, so that the "paper" manual is updated regularly, as things are added and changed during beta, with content patches, etc.