Dull,
The thing about paint is that many different brands can create similar colours but the quality of the paint itself can vary enormously between different suppliers and manufacturers. I would assume that like most people doing up a machine you have spent many hours of hard work and probably a fair bit of money in getting to the final paint stage.
Take it from one with experience who learned the hard way that last thing you want to do having invested so much to get to this stage is to go and finish the job with a cheap coat of paint that will either bubble at the first sign of cutting fluid or simply not provide you with a good durable finish.
Tractol may well be a good paint, I don't know as it's not a brand I have used but what I can tell you is the Paragon paint being sold by SEP is the proper job. I have been very impressed by the quality of finish, the ease of use and the colour match, it's by far the best paint I have ever used. As soon as you pop the lid off you can tell it's been made to a standard and not a price simply by its viscosity. Some cheap paints slosh in the tin like water, Paragon Paint is thick. It's supposed to be good to go as it is from the tin but I found that by adding just a tot of thinners it brushed out better, saying that I used it over winter and my workshop was cold at the time.
I know most of us operate on a budget but IMO the final finish of a machine restoration is not a an area to scrimp on, let's face it you don't want to be doing the job again in a few months time because the cheap paint you bought from your local outlet peels off as soon as you show it any oil or cutting fluid. Having used Paragon paint I wouldn't consider using anything else again.
The old saying of "you get what you pay for" is certainly true for paint products.