To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as a flashback cost), add any cost increases (such as kicker costs), then apply any cost reductions (such as that of Emet-Selch of the Third Seat's first ability)
The first is a triggered ability: "When this permanent enters, target player may search their library for a card named [name], reveal it, put it into their hand, then shuffle." Note that the target player searches their library (which may be affected by effects such as that of Stranglehold) and that the card they find is revealed, even though these words aren't included in the ability's reminder text
Joshua, Phoenixs Dominant kinda powercreeps Tersa Lightshatter in RW decks already, and Ive played her a grand total of once in my Hofri deck
Rays Of Judgement Mana Value: 3R Rarity: Rare Type: Instant Card Text: Rays of Judgment deals 5 damage to target creature and X damage to its controller, where X is the number of Equipment you control
Hopefully these options give you ideas on how to best handle your storage needs
