For anyone interested
I've been laying longshot neurals for the last few days with some outstanding results.
The rules I've used are
1. The two longest priced horses in the neurals page for each race
2. Minimum field size 8
3. 21.0 dollars and longer on Betfair 5 seconds before the start.
The results so far are
235 lays
1 loser @ 23.0
Median price of the lays has been 75.0.
There are lots of small wins of course but betting to a liability of 20% of my bank the bank has increased by about 72% in 4 days. I have reset the liability at the start of each day in line with the bank