The radials are really to establish a better ground plane from what I understand but they also give you a great grounding system. If you do end up with rebar in the concrete you should bond that too. Every little bit helps.
You could simply bond it to the "J" bolts you set in the concrete to mount the tower.
If you end up with a total of 20' in the base, tied together, it is technically a Ufer (concrete encased electrode.
Around here they are always building something so spare rebar and J bolts end up in the dumpster all the time.
I can send you some J bolts if you want. Rebar would kill us with shipping tho ;-)
