Much time has passed since original post here, but in case you remain on this forum, letting you know that we have much in common.
My '64
Sovereign (purchased early this year) was just behind yours in production in CA as the serial no. shows it no. I42 S 7077. Pretty neat, yes? I'd sure love an update on your progress, especially since I'm just starting restoration. Fortunately, mine remains unaltered from original with most everything intact.
Would you post some pics or contact me?
Thanks!
Lori