Im already in this kind of egies for some time now and I can say that with 8 currencies which s masterpiece is into, you've too much pairs and plays possibly in a drama. Im focused on 21 pairs and 7 currencies. I dont play NZD. But this is not a issue.
What're undergoing is and what you will surely be ready about:
1. Problem of backtesting. You backtest this as it looks for the market.
2. Lots of noise in the egies: Lots of orders as 21 pairs is actually a lot.
3. Lots of testing that is forwards. (Im not a developer, but found outstanding one on FF. I was able to picture one EA with situations, so that I could forward test it. I recommend this). At the peak time of testing I had 4 computers operating with 100 EAs running im at the 4th stage now, so actually dont need the pawar anymore. .
4. Lots of ideas which were scratched in various phases of testing that is forwards. (Mostly on TFs and worth ) (my indexes dont have 100-0 ratio, but are freefloaters).
5. I am concentrating winning rate with R:R around 1:1 and higher. The goal is over 70 percents.