Congrats, these are great bikes.
For paint, since it's been repainted and you want to change it, it's a blank canvas I guess -- but I am partial to stock color, especially Candy Bacchus Olive (and then Flake Matador Red). There was a stock silver color in Europe but it didn't make it to the States. And there are sellers who make stock paints, even in spray cans. I haven't gone down that route yet but am going to shortly with some spares. The fender was a an odd choice unless it's hiding a repair.
How's the exhaust? If they're stock and in good shape that's quite a score.
A lot of stuff is still available, including repops like the David Silver Spares master cylinders (I've had good luck with a couple). Some stuff (like stock fenders in decent shape) comes up for sale, and if you're patient you can find something for a reasonable price (I just sold one with a small ding on the backside that wasn{t really visible for $50).
And definitely keeping to the stock tire size is the way to go. And keep the points. Once you get them dialed in they don't make a lot of power but they sure run smoothly.