AR
I am glad to see that you are willing to go back and change what may be a mistake. I do not like to give specific instructions online for a job I cannot see. Here is what I will do.
Size the insulated equipment grounding conductor based on the overcurrent device to table 250.122
If the existing bonding conductor you have is insulated, you may be able to use that as an 'oversized' equipment grounding conductor.
680.42 refers one back to 680.26 for bonding of the outdoor hottub. Follow those requirements and you should be good to go.
Pierre
