Jerry,
I tried Holts and just about every other brand (I now have a fine collection of silver cans with one squirt used).I ended up getting it matched at a car paint shop, bought a spray gun and a litre of the paint/thinners and had a go. (did three frames at once). The colour match is great and they look fine.
My son tried another method on his bikes. He got the paint colour matched and put into spray cans,it turned out a very poor finish and he is now looking at repainting with the gun. With your parts prepared to paint by you, a spray painter (with matched paint) may also be a viable option ... it all comes to $$$$ and what sort of resto you are trying to achieve.
Original Bultaco paint was very low grade,It is more of a grey than a silver, some people say it was shoe polish ! The colour also varied between bikes and models.
Like felix, this is probably not helping you much and is just my experience.