If your looking at a Grizzly as part of a complete "Light Stuff" package it should come with a pretty nice Dead Zone scope as part of the package.
Personally, I prefer the Dead Zone or even a Varizone for that matter,
over a tactzone. I think the clearity is way better with either of those 2 Excal. models.
If indeed, you feel the need to up-grade your scope
the Hawke XB 30 or XB 1 are both illuminated and I think much superior to the tactzone.
If illumination is not a "Must Have" then simply buy the Nikon "Bolt" model for much less money than any of the illuminated scopes I have mentioned and never look back.
Even though it lacks a speed ring, the clarity and quality is great in these scopes and their crosshairs are just about ideally spaced with a 300 fps. crossboow in mind.
If the speed ring is actually needed in your opinion, then the Leupold Crossbones becomes " THE ONE " and IMO, I would have near the top of my list
as far as non-illuminated scope up-grades out there go.
Now there are more expensive alternatives available if you have deep pockets
but I feel these are great values for the money spent. I hope this helps regardless of the Moodel Excalibur you choose.
BTW, all suggested include a lifetime warranty you can really count on.
Camo Micro 335 gen. ll " XB30 SR Pro, TT
Camo Matrix 350 SE Leupold Crossbones
Camo Matrix 380 & XB30 SR Pro, w/Boo Trigger
all w/Camo Munch mounts
Sweet 44 yr. old 73 Bronco