i use the viper and wouldn't trade it for the world.The only accessory i use is my harness with the climbing rope.Never bothered with the vest until this year, always was in too much of a rush to bother with a safety harness but with the cimbing rope it does not reall slow things down, plus now i have kids so gotta be careful. Good Luck
As for accessories not really much you need aside, just the climber and safety harness. I would suggest you go out and get the hunter safety system harness. Its easy to use and doesnt get all tangled like the free ones you get with your stand.
Make sure you practice a few times before you take it out. And always always make sure you have the top and bottom sections connected in some way. You do not wanna be 15 - 20 foot up and have the bottom slide down. It will ruin your day real quick.
As you start using your climber you will get better. My other advice, get into a routine, always keep stuff in the same pockets and prepare your gear before going out each time. Good luck to you.