If you analyse the races on a continuing basis you will note the folly of backing topweights with 3kg apprentices employed to allay the impost of topweights in handicap races(eg. 61kg and above).
Whilst the utilisation of a "3kg boy" will definitely benefit the horse in respect of weight carried, the loss of judgment, cunning, experience and acumen displayed by the senior jockeys will outway any percieved benefit of employing this category of rider in the long-term.
I recommend that any form student think very closely about this in the future.

Cheers