Brightsides is easy to touch up. I h\ave found the key is to do it in the sahde, or the coolest part of the day, and use a 10%-15% thinned cup of paint and a foam brush with a light load- go back and forth, back and forth, and massage it in, if that makes any sense. Don't get panicky, let it flow out once the coverage is good and there are no bubbles. You can always fix it later, but you can't really fix it on the fly.
If you're challenged by brightside, thank neptune you didn't try gelcoat. now do you understand why amateurs paint?