Differences between number sets

ValKalinic

What are the differences between the following OpenType number sets?

1. Small Capitals numbers (c2sc) and Denominators (dnom)
2. Numerators (nums) and Superscript (sups)

As I understand it, SmallCaps and Denoms share the same baseline, but not necessarily the height, depending on the design. The former is aligned with SC letters, and the latter with the lower numerals in fractional form.
Numerators and Superiors should share their size, but the vertical position is aligned with the upper number of the fractional form in the former case, and with how the superscript relates to standard letters in the latter.
Am I missing something important? Thank you.

Thomas Phinney

Yes, your positioning understanding is correct.

Positioning and sizing of numerators and denominators should match that of the pre-built fractions such as 1/2.

Small cap numbers are generally sized the same height as your small caps. (Or possibly a little larger.) With an average font, your x-height might be at .5 em vertical, and your small cap height would be less than 10% more than that. Small cap numbers would thus be a bit bigger than your lowercase.

Numerators and denominators are typically a bit smaller than the x-height, maybe .4 em is average height. Denominators are usually on the baseline. Given normal diagonal fractions, they can be a tad taller than 1/2 the full numeral height, but not by very much at all.

ValKalinic

@Thomas Phinney
Thank you very much for your thoroughly explained helpful answer.