ECSC index
1) Broad market vs. specialized
If our index include only top names in the fashion of Dow, then we are creating a Dow like index. That is, we are not a broad market index for Chinese small caps like S&P, Russel 2000, and Shanghai composite is more or less broad market index.
2) Weighting -
If we only include top 10 amigos (or the expanded version.) Then our index will consist relative few stocks.
I would suggest equal weight for those stocks, that is, all stocks will consist of the same percentage at the stock of the index. Alternatively, we can weighting using market cap, or weight using popularity (votes). T
Dow more or less uses equal weighting, S&P, and Shanghai uses market cap for weighting.
3) Rebalance
If we are using a selective few stocks, then question will arise: if and when are we going to change the composition of the stocks (addition or removal of stocks). How and when are we going to rebalance the portfolio (the weight.)