Mark, I think applying filters to numbers would even be better. I've generally found that no.2 should not be layed especially on Saturdays. Maybe a filter regarding its weight..?

Coochiemudlo, Thorn's Laying selection method is:

1) No.1
2) Maximum of 12 runners.
3) Placed last start.
4) Now starting from barriers 1-3.

The rules are illogical but Thorn has Wed and Sat results for the past few years which shows the method is in profit for both days. I've been laying the method every day since Tues 11 Nov with success.