Log in RULINGS 2016-11-08 Spells you cast from your hand this turn will gain cascade even if Yidris leaves the battlefield
Since it is Commander theres no shortage of interactivity either with counter magic, removal, big board wipes, and game wide sweepers lurking in everyones hand
Reach for the Sky for me is a bit too expensive, the effect is powerful and will certainly generate blow out scenarios, but the downside of a 4 mana combat trick is that if your opponent has instant speed removal, you are in trouble and often end up with bad trades
Tables vary in texture and cleanliness, which affects card handling
If you dropped Bramblem Familiar earlier in the game to help smooth out your mana a bit, you can always discard a card to bounce it back to your hand, giving you an opportunity to cast Fetch Quest again
And normal cards that care about counters look to add them with things like populate and Doubling Season, and this heads somewhere else