Tenacious, you need to allot some kind of figures to each of your factors, add the total for all horses in the race then divide each horses total by the race total this will give you a percentage you can convert to odds. Your last statement is correct about backing the horses that you get better prices for than what you rate them at. Some good sites for free horse ratings are ozeform, Tasmanian tote site. Hope this helps and good luck, youll certainly need it.