Every new MTG set has a nice, big dragon at mythic rarity, often a 5/5 for 5 mana thats one of the most expensive cards of the set
It is not a foolproof method, and as your skills grow you will gradually, stay open, for longer and longer, but when you are new I think 5 picks is enough
Its reminiscent of the notorious Aetherworks Marvel, albeit with a much higher cost and a much higher potential impact
And be sure to have a few extra copies handy in case your opponents try to counter your Counterspell
"If you would draw a ( or the first) card during your draw step, instead you may..." doesn't usually steal things permanently
With a 100-card deck, the life cost would be a problem if I needed it to find one particular card