If I deduce correctly, your outside corners will be, in effect, on 12 x 16 centers. Center posts make two 12 x 8 areas. With the 2' overhang you then get a 16 x 20 shaded space.

So, your longest unsupported span will be 12' with 2 x 8 lumber.

What is your on-center plan for the rafters? You don't need to worry about snow load in your climate (just wind)and the span chart I looked at indicates with 16" centers, using 2 x 8 lumber, you can span approximately 23'; and on 24" centers, 21 feet.

From the linked photos you can see our pergola. The posts are on 8' x 12' centers with a 2' overhang on the corners. All lumber is 2 x 12 but with the rafters "nested", each is in effect, 2 x 6 though I have a lag screw at each intersection to tie the members together. No problem after 5 years and I reside in a snow zone.

Plan to install footings for the posts before building the paver patio. Hope this information helps. Good luck.

Here is a link that might be useful: Pergola

I wanna see 2x8's spanning 23'. Sounds bogus to me.

most on a 2x8 should be about 12' span if I remember correctly