I have heard that the rule of thumb on the qualifiers is to offer 2 grades down. So for an 8 OC= 6. There was a PSA 6 that sold on Ebay recently for $66.00. It will be interesting to see where yours ends to see if this way of pricing is still similar. I hope yours does better!
Good luck!
Edited to add....I think yours has really nice eye appeal and color even with the centering!