and what would be the size of this batch?

May I know what do you mean by a decentralized exchange? I believe most crypto exchanges are by default not centralised?

I think this works very well - simply set google alerts for "ICO" and voila, you will get a constant newsflow on ICOs! 
However, there's simply a lot to sieve through and an effective way to understand ICOs in-depth would be to attend events held by the companies offering the ICOs. Would need to get access to invitation though.