Viscera Seer is what you need
The value of X is calculated only once, as Consuming Corruption resolves
But, if you want to really get silly, my favorite card to play with the supersized succulent is going to be Sovereign Okinec Ahau

$17.99 Najeela, the Blade-Blossom (0042 - Cloud Strife) Final Fantasy Through the Ages $10.99 Isshin, Two Heavens as One (0054 - Lightning, Lone Commando) Final Fantasy Through the Ages $3.99 Kenrith, the Returned King (0023 - Noctis Lucis Caelum) Final Fantasy Through the Ages $13.99 Tymna the Weaver (0018 - Cecil Harvey) Final Fantasy Through the Ages $4.49 Ishai, Ojutai Dragonspeaker (0053 - Benedikta Harman) Final Fantasy Through the Ages $6.49 Gix, Yawgmoth Praetor (0035 - The Shadow Lord) Final Fantasy Through the Ages $3.99 Bruse Tarl, Boorish Herder (0050 - Hugo Kupka) Final Fantasy Through the Ages $8.49 Loran of the Third Path (0024 - Garnet Til Alexandros 17th) Final Fantasy Through the Ages $10.99 Chromatic Lantern (0061 - Crystal of Altar Cave) Final Fantasy Through the Ages $2.29 Traxos, Scourge of Kroog (0020 - Giant of Babil) Final Fantasy Through the Ages $2.99 Yuriko, the Tiger's Shadow (0060 - Yuffie Kisaragi) Final Fantasy Through the Ages $4.99 Mangara, the Diplomat (0025 - Minwu, Rebellion Strategist) Final Fantasy Through the Ages 0 results found

As a very general rule for Limited, I would look to play something like this: 1 mana: 02 2 mana: 46 3 mana: 35 4 mana: 24 5 mana 13 6+ mana: 02 That's far from hard and fast, but it's a good place to start