Further thoughts on this as I progress with some data, at first sights it seems logical i.e. the "book" is usually
around 120% so back the first 4 only at least 20% over and you can't lose eh? eventually.

But it's starting to remind me of a plan that I used for a while with pre-post favs, i.e. overall they (PP Favs.) showed a
loss of around 10%, with an average price of (from memory) of around 2-1, so the idea was to only back em' when you
could get at least 5-2, seems logical,.......... er....... problem was I started to show an INCREASED LOT. Didn't take
too long to realise that the higher the price the lower the S/R and so the greater the LOT.

I haven't quite figured out if the case will be the same with this one but I suspect it will (unfortunately)

One thing though, using the same idea, but backing on Wed/Sat with bet fair SP & with your Min. price stipulation,
(as explained by Bhagwan)
that would take a lot of the work out of it and in a better pool may just tilt it the right way.