Pre-Post prices are the ones you want. Too many runners shorten for SP to be any guide. There are differing SP prices around, but if you use the same source all the time [whatever it is], It should all come out in the wash as a similar result over time.

For this thread I'm just using the WA PP odds on Sat. [mainly, but if the odds are there on the site I'll throw in Wed.]. I've found Sund, and Mon.[ along with WA] very poor days for this system, especially Sund. All 3 should be avoided.