Any ex-spread compilers on the boards?

I would like to understand how the spread firms calculate their spread indices for the gg's.

Say it is a 50:30:20:10 index. How do they calculate the figures accurately? Do they use both the win and the place odds to compile these?

I notice that Spreadfair's prices seem to be linked to Betfair movements and a bot controls the price updates for them. Would this be a fair assumption?

I've seen the calculation for simple index markets somewhere, but can't remember how to do it. I think it is based on the total points available for the index, relative to the odds.

But I could be talking tosh. :?

Guess not then.

Will dig around in my library. I'm sure I saw this in a fairly recent publication.

You are at least being read Slarti

Unfortunately it's by me, and I have not the faintest idea about horses...

muchos gracias Riccardo,

Thought I was the only one here for a while. :)