Can I use carbon bolts on my Excalibur?
Carbon arrows come in an assortment of weights, and as long as the total mass weight is above the our minimum recommendation for your model (350 grains) and the outside diameter is large enough (.300") they shoot well. Are they worth the extra money? Maybe...maybe not, they stay straighter and penetrate slightly better, but they cost 1.5 to 2 times as much as aluminum. Excalibur is now selling a carbon shaft by Gold Tip which is the same O.D. as a #22 shaft (.343) and similar weight to a 2213.[*]What arrow should I use on my Exocet?
Exocets are at there best with 2216s .Heavier shafts just don't give enough extra grunt to justify their velocity loss. 2213s shoot really well but don't use less than a 100 grain point with them and don't use them on bigger game than deer.

[*]What arrow should I use on my Vixen?
The Vixen is really a toss up between 2216s and 2213s. 2216s give a little better flight and are better on heavier game like Elk, Bear and Moose, but for whitetails a little bit of "get there fast" goes a long way, so for them my vote goes to 2213s.