Is there a limit to the size of your card protector, can it completely cover your cards?
Yes there is an unstated limit. From the
TDA rule 24C
C: Players must keep live
hands in plain view at all times.
Therefore the size of the card protector may not completely cover the cards. But there is nothing in the TDA rules that says what % of the cards must be visible.
Bottom line is if the size of a card protector is called into question, the floor may make a ruling that you aren't happy with. If you think this may happen then get a ruling before you start play.