I havent worried to much about class as I think the Ave prize money does the same thing.
Weight carried is of importance but havent given it to much thought yet.. as i would like to consider the total weight (Horse and Jockey) combined, until i can find this for free i'll pass on it.

I use,
Weight rating (100 98 97 90) etc
Last start
Ave Prize money $
Win strike rate %
Time rating..

Also have been looking at last three starts %
Total runs/(win-places)%

All things to consider but a lot of work.

Some days are great?? but its still Roulette at the end of the day.(luck)
As the best Runner selected doesn't always mean its the right one to back so its like which one is the correct one mmmmmmmmm

GD4TH