Finally, after two weeks of trying, (and failing with numerous fatal error messages), i've finally managed to create a flat/jumps schedule that works!! It has the US triple crown, and at the moment seems to be working fine (fingers crossed). PS - I used the spreadsheet, by the way!

What was the secret? lol I just started making mine.

The most important part is to check the spellings of the race names! They have to match up perfectly from schedule to showcase, just one wrong letter will cause it to crash. Also the months have to match perfectly as well. If you look at the default showcases a lot of the months don't match up with the default schedules, so you have to change all these as well. And finally your end date, if your flat season ends on, say, November 16th, then your final flat showcase needs to be on the 15th. Otherwise you will get the "cannot find end marker" error! Apart from that it's simple! In the end I copy and pasted the race names from the showcase to the schedule to avoid spelling mistakes, and it worked!

Legend, does your schedule include a full jumps schedule, including all Cheltenham and Aintree races?

If so, I would really appreciate a copy if possible?

Did you manage to create a combined schedule where the jumps season starts in autumn and ends in spring, so that novices keep hold of their novice status from December into January? And where the end of the flat season overlaps with the start of the jumps season, and the end of the jumps season overlaps with the start of the flat season?

It's a combined Flat/Jumps schedule, with the flat and Jumps seasons as they are in the default schedule. But i'm sure you could create one with the jumps season running as it does in the Jumps only game. I'll try it out later on. The Jumps only one is fairly basic at the moment, but I intend to improve on it now I know it works! As soon as i've tested it fully for a few seasons i'll see if someone can host it for download.