Welcome to the forum. I think that you’ve got it right but for most people, including myself, having to use Lumariver or ArgyllCMS to create your own colour profiles with an IT8 target is a step too far. If you do this yourself it would be great if you could go through the process.
Another point of view might be that it isn’t in any case worth the erffort and that instead simply using modern software techniques to make the best of the slide might be a better option. Linear profiles can help a lot here which is why NLP can be so useful for slides as well as negatives.
Have you seen this thread?