hi
look at the information and you will see a pattern and official rating does tie in with class.
Handicaps: Those races where the weight carried is determined by the official rating of the horse. Handicaps are grouped into classes, with class one being for the highest rated and class seven for the lowest.
class 1 = 96 to 110+
class 2 = 86 to 110
class 3 = 76 to 95
class 4 = 66 to 85
class 5 = 56 to 75
class 6 = 46 to 65
class 7 = 0 to 45 but most are classified stakes not handicap
so looking at the official rating if you set a maximum of 90 then any race class would be 3 to 7 with a small chance of missing a class 3 race.
if you wanted class 3 , 2 and 1 then the official rating would be minimum 86
mcbee