Extra link is a nice solution if you're worried about it-- It's generally not too hard to pick a chain length that will let you use the full range of gears you want to use for training and racing. The original Felt Tk2 had short dropouts, so two chains might be required for covering the full range on those. Chaintugs can be a pain for quick wheel changes, but they will keep you from slipping.
20mm Conti supersonics may be an option. Another option may be to add an extra link to your chain to get your tire away from the frame (if you are already forward in your dropouts). Another option would be to get one of those doohickeys for your drop outs to lock the wheel in place.