For used sails
in the bay area you could check with Marchal Sailmakers in Alameda. Dominic is an honest guy with decades of experience.
It's very challenging to find a good used sail for a boat like yours. You need a decent cruising sail and people typically don't get rid of them until they're pretty worn out. It's not just condition of the cloth but the sail shape that's a concern.
Even if you find something that fits, you won't know if the sheeting angles are proper until you try it out. If they're not, you'll need to add fairlead track or a padeye.
Luff tape is the least of your worries. Most likely it will be a #6 for a boat that size. You measure the diameter with a set of calipers or fine rule
Most likely any used headsail will need a new suncover on the leech and foot. That will probably run close to $10/foot.
What many people learn the hard way is that a used sail can often cost 50%-80% of what a new sail that is custom made to fit the boat. In some cases I've seen people spend more than the price
of a new sail by the time they're done.
Something else to keep in mind is that you're in the SF Bay
Area. That means some serous wind
and chop. Sails made for boats in Southern Cal
don't always fare well in San Francisco
Bay. Most boats in the bay will carry something like a 100%'ish jib and for a boat like yours, it will usually be a cloth close to 8oz.