Theres a pretty wide range for how to make a proxy. Some people write the name and abilities on a piece of paper covering a reversed card in a sleeve, some write the name of a card on the back of a bulk card like a basic land, and many people just print out the card in question
The reward for jumping through these hoops is a powerful recursion engine that lets you cast any Knight creature from your graveyard, creating a resilient, grindy board state
Im considering it for my own Xryis Writhing Storm deck even if the timing is off
If the cards were discarding to Olivia in response to creatures entering the battlefield can be cast later in the game, then were never truly losing card advantage
They can be somewhat pricey and are considered collectors items
In other words, the most recent release of Bill made it a Supporter, so older versions of Bill are now to be played as a Supporter