Thanks lads. Below are the initial stages of the selection process.

Discard all races that are not 8-14 runners.
(If the initial field is 16-18 and we have early NRs bringing field size down to 14, these can be included. If value can be found in a 7 runner race with a decent field, I will include that).

Discard all maidens were the majority are 1st time out.
(if 60-70% of the field have at least 2 runs under their belt, these can be included if there is value to be found).

Check the early betting forecast in the papers or on RP website. I will be using RP as I find this to be more accurate.
(in the event of there being joint or co 3rd fav’s, I will use the speed ratings here to identify the horse with the highest rating as my initial selection).

That initial filtering process, depending on the number of meetings and quality of races, should leave us an average of 12+ contenders to filter out our selections from.

When I was doing this a few years back, it was on the flat, so I’ll need to look to see if NH needs to be treated differently.