One line answer: Do not think too much about keywords vs heading tags. Create content which will be useful for the user.
Meaning:
You can have h1, few h2 and so on. But don't think too much as you need to place keywords in each. Try to have generic headings which may or may not include keywords in each.
Instead of worrying about keywords and heading tags too much create useful content by having appropriate text, bullet points, images, videos (Very useful in above industry).
If you will have useful content it will rank well rather than stuffing keywords in each heading.
Example:
Let's say you have got 2 main keywords for the page and few secondary keywords then you may follow following approach:
H1: Your main keywords, and then have rich content under this.
h2: Your secondary keywords with few extra words, again have rich content.
h2, h3 etc: Keep it generic.
Focus more on actual content which will be the point of difference. Quality content can rank well regardless.