TexasRock, I think maybe another standpipe to that overflow will help (effectively the same as lowering flow through one standpipe), but that you should try a bunch of this other stuff before getting using another overflow, unless you want redundancy or something too.

vidiots - Reverse Y on the downpipe is sweet. A bunch of great ideas: thanks. I sugmerge my siphon break fwiw so its quieter. I have redundant holes of course, to avoid issues with clogging.