Automated Dutching

[robertson21]

Hi all. Looking for a quick bit of advice if I may. I like dutching the first few favourites in horse racing. Having seen Peters recent video, I wanted to fully automate this. I'm fine with about 90% of the automation settings, but I would like to set it to back the favs to around 80% of the book, as opposed to specifying an exact number to back. Any ideas how to do this please? Thanks in advance