1. ask one question per thread.
2. give each thread a title that gives us some idea what it is about.
3. give more context. #2 makes little sense as it stands. It is not possible to give a satisfactory answer to #3 without more context.
The answer to #1, depending on the situation referred to could be:
I should have seen it glow/glowing.
I should have seen (that) it glowed/was glowing.
Student or Learner