The less acceleration they have, the better Gloom is, but if they have tons of artifact acceleration to play through Gloom, its better to leave in the sideboard in favor of something like Hymn to Tourach, which can proactively strip away countermagic and spot removal
If you want the fastest, easiest small-to-medium order (especially in the U.S.) PrintingProxies is built for speed and convenience
If this card is sent to the GY as material for the Link Summon of a WATER monster: You can excavate the top 3 cards of your Deck, and if you do, you can add 1 excavated "Marincess" card to your hand, also shuffle the rest into your Deck
The idea behind this is to create infinite tokens that can be sacrificed to inflict damage
As with many supporter cards, he allows players to shuffle an unwanted hand back into their deck and draw as many cards as prize cards remaining on the table