I have 214 earned merits. Let's assume I have included 30 persons in my trust list. How will system choose my vote, I mean by which criteria, since I have capability of voting for 21 member. How someone from my 30 members will be excluded/included?
Pay no attention to the man behind the curtain.

When building your trust list, I tend to encourage people not to worry about little details like this, and instead just think about the system in broad strokes. If this results in poor outcomes, then that's a problem on my end.