So I could be wrong but I don't think there's a reining rule that states that you specifically NEED to wear spurs … If she gets along fine without them and you feel there's no need for them outside the show pen I wouldn't bother with them. If she just needs a bit of a wake-up to get a little more refined, you can ride with a dressage whip in each hand and when you apply calf, if she doesn't respond, you can tap with the dressage whip to wake her up.
Now, me personally, I feel that every horse should accept spurs. It's kind of like a flank cinch - I might not ever need to ride in one, but if that situation occurs, I want to know my horse isn't going to freak out, so I train them to accept it. I also feel that a horse will never get as soft and supple through his body using dressage whips as he will with spurs. You can desensitize them to spurs from the ground by asking the horse to walk a small circle around you and holding the spur in your hand. As you walk, gently press the spur against the horse's side in the areas you normally do to ask the horse to yield his hindquarters, shoulder, and ribcage. Do one area a couple times then move to another. Be sure to do both sides.
For the crankiness under saddle, you fix the biggest problem first. I NEVER allow bucking when I put my leg on, so that's the one I'd fix first. I take a long quirt or the ends of my reins and if the horse bucks when I put my leg on, I over-under him hard, just once. Every time that hind end pops up, I over-under him. If it happens more than a few times in a row I'll gallop him hard around the arena a few times (for a lazy horse) or do rollbacks on the fence for a while (for a hot horse). KEEP YOUR SPURS OFF HIM when you are reprimanding him for bucking at your spurs, or you'll just create a rodeo. The horse has its own brain and I think he's allowed to show me he doesn't like things - but never in a way that will get me hurt. Head shaking is fine. Bucking is not.