There are no hard and fast rules with the picks. They will tend to appear on the Shortlist 90% of the time. What you say above is correct regarding no Filly Only and no Am/App races.
I should clarify, especially after the last few days,what I mean about <7.0 BSP selections. I said it was more profitable but it is more accurate to say that it is more stable as in, fewer losing runs and a consistent level of wins and places.
I think this site is fantastic as it saves me a lot of time finding my selections which would be possible to do using the Racing Post or Sporting Life sites as I choose selections solely on probability + value (as I see it).