Hi party .
Here are a couple of tools that are very helpful in getting your bets on more smoothly & can bet below the Betfair min amount.

Bet Trader Pro (Free) Google RacingTraders.

Betfair Rapid (Free)

Fairbot (15 day free trial) this is excellent & worth the price.

Some of the Betfair prices are amazing, sometimes double & triple to that of say the TAB.
For instance I got $8.80 for a horse that was showing $3.60 on the TAB at jump time & it won.

It is also an interesting exercise to look at the TAB fav at 30 secs till jump then compare its price to Betfair.
The difference can be 50-200% difference

I would maybe compare the Bookie price with betfair & go from there.

Cheers.

__________________
Cheers.