Targets3D,
1. proper tuning will tell you which tips to use. With a plunger, you have more latitude since you can fine tune with spring tension. For your purposes, I would try to go as light as possible.
2. As light as possible. With the type of bow you're using, and only pulling 35#, you probably won't be able to find an arrow light enough to hurt it without spending a bunch of money. Stay at or above 7gpp (245 grains) ans you should be fine.
3. Proper tuning will determine this.
4. I believe Gold Tip makes a lightweight shaft in 1535 (.600 spine) but I'm not positive. You may even be able to go to a spine weaker than that with a light enough tip.