Thanks for the replies and I have taken a lot of your ideas on board but feel that there are weaknesses in those arguments too. My overall conclusion is that level staking is really the only way to go. Actually, I feel that any non-level staking plan is really just a series of level stakes running concurrently. e.g. stake $1 $2 $3 $4 etc and over time all the $1 bets form one series of level stakes and all the $2 bets another and so on. Then again don't dismiss my plan too quickly - try it on a simple selection method like the longest price horse (3 to go) out of the top three ranked place percentage horses. Remember I do say it is probably a good idea to start again once the target price is say $21.
John