Fine. So far so good.
Regarding my original question about variation of internal contextual anchors may be you or others may vote for one of four basic variation ways. What may be the best in terms of SEO (all are good for user experience)?
Let's say a page gets 10 contextual internal links. All of the used KW-anchors are relevant, topical.
1: 10 x KW1, which is the main KW and also used in the navi!
2: 5 x KW1 and 5 x KW2
3: 10 x KW2, which should help KW2 notably
4: 2 x KW1, 5 x KW2, 3 x KW-combinations of KW1,2,3