Here are some stats for interests sake, note its on a small sample size so far since i've been keeping records.

Free Ratings 1:
No Filters
167 Races
Top Rater = 24.0% SR 1.4% LOT
2nd Rater = 21.0% SR 25.39% POT

2 Race Filters
118 Races
Top Rater = 24.6% SR 5.5% POT
2nd Rater = 23.7% SR 52.8% POT

My Own Speed Rating
167 Races
Top Rater = 17.4% SR 10.1% POT
2nd Rater = 19.2% SR 4.2% LOT

2 Race Filters
100 Races
Top Rater = 21.0% SR 38.0% POT
2nd Rater = 19.0% SR 6.6% POT

My Own Full Rating
167 Races
Top Rater = 21.6% SR 10.7% LOT
2nd Rater = 13.2% SR 32.3% LOT

2 Selection Filters
Top Rater = 33.9% SR 27.4% POT (62 Selections)
2nd Rater = 50.0% SR 128.0% POT (10 Selections)
Note the above for 2nd rater isn't very realistic and these filters are based around simply making the top rater bettable

My Version of Shaun's Rating
167 Races
Top Rater = 22.8% SR 7.1% LOT
2nd Rater = 14.4% SR 23.8% LOT

2 Selection Filters
Top Rater = 47.1% SR 10.8% POT (51 Selections)
2nd Rater = 31.8% SR 0.2% LOT (22 Selections)
Note for my version of Shaun's ratings his 3rd selection is actually quite profitable with 1 selection filter as per following:
3rd Rater = 19.3% SR 16.0% POT (88 Selections)

My Rating of Ratings (Combination of rating sources)
167 Races
Top Rater = 22.2% SR 17.9% LOT
2nd Rater = 22.8% SR 14.9% POT

2 Selection Filters
Top Rater = 36.5% SR 3.4% POT (74 Selections)
2nd Rater = 43.9% SR 15.1% POT (41 Selections)

Now obviously the above are all small sample sizes and don't really count for much at the moment but you must also remember all my prices are recorded with Tatts odds. So if you take best of tote or betfair prices and there is a solid chance most of the above are improved by another 5-10% POT. None of the above ratings sources were hard to find, put together or record its just a matter of doing it. There's also one filter i've found that seems to improve almost any selections I apply it too, and it wasn't that hard to find either.

Bit of effort is all it takes.