Resting Awareness, just keep the fingers relaxed throughout the process. Keep them open; that is separated, not touching. The fingers don't have to be perfectly straight; yes, you may curve them. Just keep them open.
Master Lin, has his fingers straight because that is more natural for him. They just hang in deeper relaxation. Don't get hung up on this though; or else, you'll miss the bigger picture: open the channels, relax, and enjoy!
Relax and enjoy the process: standing, sitting, walking, etc., etc.
Much Love....