I've been trying to work on a large map for some time. No matter what map size I use, the symbols are always the same size relative to the map. What I mean is that not depending on whether the map size is 10x10 or 20000x20000 a symbol is always, say, 1/20th of the length of the map. I've tried going to File -> Drawing Presets and changing the Symbol Scale, but that has no effect on symbol size.

Please help; I'm incapable of doing large maps because the symbols are too large.