OK, I did some more research. The difference between a fillie and a colt if you're perfect is not as much as I thought. The research is at
http://gameboy9.marpirc.net/stakwin2.zip - an Excel Spreadsheet
the totals are:
American Colt - 21.813 miles total - 21,994,000
American Fillie - 21.188 miles total - 20,664,000
European Colt - 22.625 miles total - 20,044,000
European Fillie - 22.625 miles total - 18,839,000
The fillies are less, regardless - and the european mode is worth less, regardless - so basically everybody would have to go American Colt in order to get the best score, now that wouldn't be fun, would it?
In addition, the europeans have a much different path than the americans, the fillies have a different path of tracks itself, but it's not as dramatic - so it's probably better to split european and american.
Therefore, I'm changing the poll to indicate split four ways, european/american, fillie/colt, and another option for splitting european/american, but not fillie/colt (what I'll vote for... I guess)