Performance for many tiles / chunk size

[Droggelbecher]

When I zoom out far in my application the framerate goes down drastically (in my case ~3-4 FPS), due to many render calls. It would be nice to:

a) Have chunk size configurable at programming time (so I can choose a good tradeoff for my specific game)
b) Possibly have some way of dynamically changing the chunk size at run time (not sure that makes sense / is possible?)