Davex & GD4TH,
Sorry my reply is late - Rating some mules.
Weighted Race- As you know the top weighted horses have a higher strike rate than lower weighted ones,so scale the race + above say 53.5kgs - below. (RF 53.5=1.00 ,60kgs=1.7, 50kgs= .5).
Horses weight difference.- Same weight last start =0 (RF 1.00). Up in wt. (RF 2kgs=1.36). Down in wt (RF -2kgs=.80).
I use the latter because I think weight rises say's to me good horses win & dropping in wt. dont win as often.
These should not be used solely but with other form factors.
Cyah,
Ray