This Pinsider makes Seawitch playfields and backglasses. He currently has some playfields in stock, but the colors aren’t correct to originals. He’s waiting on suggestions for playfield colors before doing another run.
https://pinside.com/pinball/forum/topic/would-you-prepay-500-us-for-a-new-stern-seawitch-or-star-gazer-playfield

Another option is to convert it to a Star Gazer. The above guy also made SG playfields but the colors are off so he’ll be redoing them as well. He also makes SG backglasses.

Another option is to convert it to a Quicksilver. Mirco sells the playfield in Pinside Marketplace and you can order a backglass from Bgresto. If you’re going to convert to a SG or QS you’ll need to order a wiring harness set from third coast pinball here on Pinside.
https://pinside.com/pinball/forum/topic/new-wire-and-harnesses

Last option is to sell the project to someone else and let them finish it.

Quicksilver is a better player than Star Gazer, but Star Gazer has the best art package (playfield, backglass and cabinet) of any of the early solid state pins. Quicksilver’s Art is, well...it has a nice personality.

Search the Quicksilver club forum for posts by drdave. He recorded the various sound effects of Quicksilver, including the bonus countdown. The first time that I spelled Quicksilver and had a bonus multiplier, I freaked out when the siren started, reached a high pitch, suddenly stopped, then started again. Once you listen to the sound effects, I think you’ll build a Quicksilver.