The value of X is determined only as Bag End Porter's triggered ability resolves
Once you have a sufficiently large enough creature, you just need a way to send it in without being blocked, like with a Rogue's Passage or any other card that can make it unblockable
Potential Interaction Another thing to consider is the not-so-different I want card A to deal with my opponents card B. If thats the case, put that card in your sideboard
Toph, Greatest Earthbender (Gruul) While shes excellent in the 99, Toph is also an intentionally clever commander
A "poly" artifact is an artifact that has an activated ability, but you didn't have to tap to use it
This works best in typal strategies that flood the board with one creature type, but beware of board wipes significantly reducing the mana you have access to