Alternatively, where it is legal "Kashtira Arise-Heart", supplemented by "Outrigger Extension" and "Goliath", could take the place of "River Stormer" as an endboard piece in this combo through the implementation of "Scrap Recycler" (as the "Gear Gigant X" search/"Platinum Gadget" summon, sending "Harvester"), "Infinitrack Trencher" (in place of "Tunneler") and "Infinitrack Crab Crane" (searched via "Harvester")
Rayquaza for example is listed as worth $700 USD on TCGPlayer, but looking at the available sellers, there are only two options: one for $5,500 and one for $25,000 as of this writing
UR Ultra Rare Dark Necrofear X DARK Level 8 [ FiendEffect ] ATK 2200 DEF 2800 Cannot be Normal Summoned/Set
In any case, I should have written the cards' last line like "You can only use each effect of "name-of-spell" once per Duel."
The team was excited and enjoyed almost all of this playtest