More about ideal point sizes can found on this thread:
viewtopic.php?f=46&t=24179&p=295065&hilit=500+points+best+size#p295065700-1000 seems to be the most fair. Nothing particularly wrong with other sizes though.
More about the new rules can be found by watching the “What’s changed?” video series on the GBHL channel:
http://www.youtube.com/user/GBHLPodcast ... 7s+changedOverall: Changes are good (Highlights: Brutal monster attacks are a wonderful new addition, much debate over shooting…)
I’m not sure what you mean by reference sheets. If you’re looking for a sheet with all the different charts I’d recommend picking up the EFGT play sheet on Ebay. If you’re talking about hero cards, most people make their own.
Lastly, in my opinion, 4x4 boards are ideal for SBG (depending on point sizes).