I stumbled on this piece of writing, an excerpt from a free ebook:
http://www.pjmracing.co.uk/index_freepage.htm yesterday which I thought might be of some use here but it is concerned only with flat h'caps:
Relates to Manner of Victory
"In fact, if we did back all the handicappers which won their last handicap at odds against and received the comment: easily, very easily, canter, comfortably, readily, unchallenged or cleverly, we would back only 71 winners from 336 bets in the period
1990-94, a strike rate of 21% with a loss of 18p per £1
staked.
Surprisingly, this loss of 18p per £1 staked is worse than the loss incurred by randomly selecting horses, which won their previous handicap at odds against (i.e. 12p loss per
£1 staked). This indicates the level of under pricing associated with this type of handicap runner.
So, the obvious selection will not necessarily yield a profit. An alternative winner to follow is one which quickens at the end of a race. A horse which exhibits this quality is harder for the handicapper to assess and is often not penalised sufficiently. Backing all horses running in a handicap which had won their previous handicap at odds against and received the comment quickened would have produced the following results: 92 winners from 421 bets, a strike rate of
22% with a profit of 0.13."
PS: GS can now be followed on Twitter as @themastarata