Silver,
As Chrome Prince said, its a living hell trying to figure the system out. But as a general rule i take 0MW races as being on par with a C5 (Metro track) and a 1MW as being closer to a C6 (Metro track). As for the 2MW and 3MW races, they tend to approach to Welter/Open rating.
The 0MWLY and 1MWLY races, especially in Brisbane, can tend to be filled by horses that are past their peak, but were once good class town horses. For that reason, its difficult to class them according to the standard scale.
That being said, as La Mer said, it is all theoretical - you really have to try and use your judgement as to the true standard of the race. A 0MW race can have many 'promising' young horses going around while a 2MWLY race can have a bunch of 'has-been' horses who are clearly past their best.
In the end, you
will have to use your instinct and judgement to gauge the standard of the race. This is not necessarily a bad thing, because that can be where you gain an advantage over the 'market'. The key, for mine, is to just get some practice at recognising the better class races from the rest.
Re your hypothetical horse, as i said above, i believe you would have to judge the standard of the other horses in the races before saying what the class change is. I have seen open and C6 races at places like Ipswich and Toowoomba full of horses who are easily town quality but are using the race as a springboard for other races. Equally, we have all seen these 50k and 100k maiden races around the place recently, which are won by, with all due respect, horses that aren't superstars. These types of races only serve to strengthen my view that using prizemoney as a selection method is seriously flawed (but thats a discussion for another day
).
In general, you should look at each race as a separate event and decide what class you perceive the horses are, while only paying only fleeting attention to the official class rating.
I know that wasn't exactly an 'up or down' answer, but that's a really grey issue in my view
. If you are looking for a quick answer, Chrome is right in saying that Metro races are
typically stronger than provincial/country races.
Hope this helps,
Sven