Grizzly rebar

Personally, I would probably go with 6011. Better penetration and it won't matter as much if there is rust, mill-scale, or other contaminants in the weld areas.
I would wonder about the stresses applied to the rebar- if you use fillets, be sure to make them big enough in both leg-length and length of fillet.
I would recommend that you don't wrap the ends of the rebar- leave a little rebar sticking out beyond the fillet. If my imagination is working properly, the stresses will be in compression on the rebar, and in shear between the rebar and base-metal. Wrapping the ends could actually weaken the assembly by creating stress-raisers in the fillet or the HAZ.

Are you sure that you want to use rebar? I've heard that it can be a real crap-shoot in the weld-ability. You probably don't want pieces of rebar breaking loose because of brittleness in the HAZ. And with rocks being dumped on them, brittleness is critical.
Unless you're using rebar that's specifically weldable. Then, "never mind".

If it is not feeding a crusher, then it is not critical if a piece of rebar breaks off. ****************************************