A sublime moment
This video has done much better than expected. It was the second of the three I scheduled to be published while I was away - hence your seeing it a bit late.
Comments (2)
I'll tend to compliment with no reference to past performance. Its internally obvious that you must have improved if now you are receiving unsolicited compliments whereas in the past you received none. Your compliment also holds more relative value if the receiver respects your ability/knowledge in that field.
it all depends on if they saw you as a mentor or teacher. If they admired your skill then it is perfectly acceptable to comment on their growth, some may even be craving it. If not ask them to show you what they did and teach it to you even if you know it already. That way you seem as you are seeking their advise.