Great info - and knowledge like yours will be beneficial to us all at some point in the future. Now that you're a member of the nicest knowledge-sharing place online for vintage Hondas, please take a look at the link below and post an introduction for us - it'll only take a few minutes and will help us get to know you and your bike better to help you in the futureI work for a spring manufacturer and we do spray paint springs all the time. Like 83XLX mentioned, you want to keep the coverage thin so stop spraying once it's all visibly covered.
It won't flake from being flexed, but it will scratch much easier than a powder coated spring. Powder coating is obviously a better choice, but spray paint is a fine do-it-yourself option if you want to keep it cheap.