How much coins i need have for comfortable staking and what is %?
Eca stacking is for whales only.
Unless you have a many mil wallet, you wont get anything.
I was staking ~ 500 000 eca for 2 month - and no luck.
Estimated wait time goes like 42 days than 28, than 18, and than 32 and never less than 14 days.
Network weight grows too fast I assume, so only whales benefit.
Just look at richlist: there is guy with ~900 000 000 eca, staking some 40 000 - 100 000 every two hours.
So, unless you have millions - not a chance.