I think the ideal size setup is around what the engine uses for cbabe and all, I'm not exactly sure what the scale is, but it's a nice balance. Try opening it and getting your sizes based on that.
@ Puppeteer: You're half right, but so is he. According to the manual:
The farther the distance between the to and from positions, the more entities must be checked in the level, and the slower the function. Use as small a distance as possible.
