I think if you already have a border of a different material, you would not need another contrasting border, though it might look cool. Maybe lay it out with one in just a small area and see if you prefer the look?

I'd stain the existing border.
The larger question is do you understand the need to remove the interior material and replace it with crushed stone that has been compacted. The removal would also need to be to a depth to anticipate the thickness of the paver

Emily is right, definitely lay it out in a small area to see which way you like it. I love the shape that the pavers make in your yard!

Your patio looks beautiful. As for the previous responder, yes, I dug down 7 inches, laid geotextile, gravel and compacted it with a plate compactor. The geo may be an overkill in the San Fran area but it was not that much.

excellent

Thank you. couple other questions. Would anybody have recommendations on the type and color of the pavers? I am thinking something with a red tone and with texture (like belgard urbana victorian).

I am also thinking of adding a small 10-12 foot wall at the far end of the patio- there is a bit of a dip at the far end and instead of building a retaining wall, I am thinking I will add a patio wall. Question I have is, do I build the wall on the gravel base and then set the pavers right upto the wall?

Pavers are not nearly as appealing as stone pavers, and have the added problem of weeds in so many joints and settling. Why not use a larger stone paver like bluestone, limestone, or gneiss or something available in your area? They are more durable, walkable, beautiful and classy. Forget about concrete unit pavers altogether.

I love your pavers, especially the circular design you made. Where did you purchase your fire pit and stools? Thank you.....

what kind and color are the pavers- looks really nice

100% agree with Brown Richardson & Rowe's comment above....natural stone pavers will add warmth and character and can be surprisingly affordable compared to manufactured products.

While I prefer natural stone too, concrete pavers are generally easier for a homeowner project. Use polymeric sand to finish the joints and you shouldn't have much issue with weeds.

We used concrete pavers for our patio area. They come in grays, reds, blues and it is a matter of preference. It's been years now and, with the sand, we have no weed issues. If you choose to build a wall, you can use the gravel for a base with thinset or regular concrete- again to go with the paver color- to stabilize. Also determine if you will seal the concrete. It will intensify the color somewhat and can even give it a wet look without the slippery-ness and therefore affect the end result.. We did not use a contrasting border and have been happy with that decision. Your area is not overly large and I would consider that with furniture and plants it needs form, but not too much "action".

Acid stain one line of the existing pavers.