I've been disecting the 72 candy bachaus olive for a couple of months (been busy)....
It appears as though Honda went a LITTLE candy crazy during the early 70s. I'm not even sure if the (Do-Do) brown is a single stage... needless to say, if you want to get close, your gonna have to do a little "detective" work. FIRST, if this is a candy paint, bad news, touch up is out of the question.. 1, the paint is almost non existent, 2, unless it has been out of the UV RAYS... it's lost pigment and is partially faded... you may be able to match the color, but the oxidation pigment percentage..no.
I made plenty inquiries, it is a small niche market... yes some people do "match" the colors, they keep these secrets very close to the vest... it their livelihood, and I'm sure it has taken a lot of work to discover these formulas..
Yes, they will do it for you .. but it will also cost a pretty penny..
Get some 1500 wet sandpaper.. lightly sand some of the top "candy" red.. spread it on a piece of white paper let it dry.. you now have a slight/close sample of the top coat "candy"...you can either look at a chip book, or have it matched...
the next step is the underlying base pigment.
This is gonna be a little harder, especially if it has matalics...I used "cotton tipped swabs", and laquor thinner to lightly remove the top candy layer... the base color may not be exact.. but it will give you a place to start.
Also, if you can, keep one side of the tank untouched... this will be your reference to match your mixed pigments to.. once you are happy.. take lots of notes.. and strip all the old liquor paint, as the new stuff doesn't like it..
Good luck
I would suggest reading the thread I started, it HAD pics.. (still looking at getting that sorted out)... it's got a lot more info