I use the R.L.W. angle on the R+S website,
As a filter for my back system for a long time.

It is very useful in eliminating horses who are,
Top 1-5 for api w% pl% p/post etc.

Just a filter to cut out horses who rate well,
With me and pass most early qualifying rules.

Not sure as a lay system (i don't do that) but sounds logical,
Laying horses who have not won for a while?.

Would probably need subsidiary rules as well,
Price distance fld/size nos of starts age etc and how,
Many R.L.W. you are prepared to conceed before laying.

Cheers.