I rate all horses on the actual weight carried after allowances.
I used to penalise 3Kg apprentices 0.95Kg, 2Kg apprentices 0.35Kg and 1.5Kg apprentices 0.325Kg.
Now I assess each jockey on their performance over past races. I keep an average of whether their latest (up to 100) horses did better or worse than expected when they rode them. I limit the bonus or penalty to + or - 3Kg in case the jockey hasn't had many rides to form a good average but I usually find the range is + or - 2Kg from the best jockey to the newest apprentice. All against actual weight carried.

KV