FWIW, I think in the average low-stakes live game (probably up to at least $500NL) there will be very, very
few players capable of picking up tells
like those and the benefits of using a card protector easily outweigh the downsides - especially if you're sitting in one of the seats immediately to the left or right of the dealer.
The tells are also easily countered by simply not
doing those things: cap your cards immediately before you take your first action in the hand (don't look at your cards, decide you're going to play and cap them before the action gets to you, for example, unless you plan on doing that with hands you're going to fold as well) and then don't touch them or the card protector again until your involvement in the hand is over. It's really that simple.