All of your sentences are grammatical and correct as written. I do have some general comments, however.
The 2nd sentence doesn't work well for me - there's a disconnect between 'undertone' and 'overweening'. 'Undertone' implies subtlety, whereas 'overweening' implies blatant display of emotion.
Also, your usage of 'jot' strikes me as uncommon. I think 'jot' is used much more commonly as a synonym for 'write' than it it for 'small amount'. I would suggest substituting 'whit' for 'jot'.
My final comment would be use of 'overweening' - are you just wanting to practice this adjective? It's a pretty rare adjective - rare enough that I'll confess to having looked it up, as I'd never actually heard it before.
Student or Learner