I know exactly where CP is coming from, as a mate and I used to do exactly the same thing years ago, and I would still do it now,except go to Richmond, Dapto, Gosford etc and there is now 1 or 2 bookies.
Used to be 20+.
Ask for a $200 bet and they crap themselves.
Wenty Park has now only got about 6 local bookies and 2 interstate.
To do what CP said you must have fixed odds and the trouble today if you have a few outs and the bet builds you CANNOT get set.

Cheers