Benny, top marks for trying, and what I like about your enquiries is that they are simple, (i'm sure this is the way to go)

I haven't got full data banks as mine are from my own system selections or ratings selections.

In all cases the POT situation is improved when the rule "LAST START WIINNER, or beaten marigin less than 3.5 lengths is applied, but across the board NO -WAY does this show a profit.

My bit of free advise is to START with a good ratings service, in which case you are starting (*probably) with a small level stakes profit, then apply your ideas (as you don't like to call em filters) as the worst you can do is show the small POT that the ratings produces anyway!!!! good luck!