Just a thought but if you can get an electric gauge that matches what you have I would and did go electric. Plastic and
copper both can and do work but as you know they can make a mess.
By the way, your 63 looks exactly like my 63 except I like your wheels better. I have Crager wheels on mine and when I get new tires (soon) I'll be replacing them, I've had enough of the slotted stud holes.
Take Care
Dennis C.