I have been debating the Surf 90s as well for a 12 string build. The other option I am considering are the GFS Memphis. They are aiming for the low Rick output of 4-5.5. figured I would throw that into consideration for you as well. Good luck with the build!
https://www.guitarfetish.com/KP--Mem...y_p_21928.html
(GFS also just got everything back in stock yesterday)