Typically you're going to want to wait until the end of the opponents turn (or during his or her combat phase, if you really need to block with one of your tapping creatures) so you can get an untap phase in
Stealing permanents, temporarily Primary: Red Red takes control of permanents, mostly creatures, for the turn, gives them haste, and then returns them at end of turn
(4/27/2018) The token gains haste indefinitely, and this effect isn't copiable
But Crown Zenith has a bit of a catch: not only is there a 159 card set in the base collection (or 160 if you count in the Secret Rare card), but there are also an additional 70 cards to collect as part of the Galarian Gallery subset bring the total number of cards to 230
The reason for this is mainly that since the printing of Ragavan, Nimble Pilferer, Dragons Rage Channeler and Murktide Regent the tempo archetype reinvented itself in being primarily blue-red and making Deaths Shadow not a necessary creature for tempo shells anymore
This fits the pattern established by Dragonlord's Prerogative, Draconic Roar, and Scaleguard Sentinels in that these new Dragon-oriented spells are generally better than their counterparts Opportunity, Searing Blaze, and Kalonian Tusker if you control a Dragon, but worse if you do not