Mazel Tov. Don’t be impressed by what ppl say you “have” to do. What is accepted in the chasan’s circles is what you want to find out, to avoid disappointing him. What ppl here write is limited to what they are familiar with and may be irrelevant to you.
I agree that atoro on a talis is minhag among those who are chasidish or the grandfather was chasidish in Europe.
If you wish to give a watch, many chasanim today prefer a steel band. Again, it depends on what is prevalent in his and his parents’ circles.
Some kallahs like to buy the chasan a silverbecher. Don’t let the silver store talk you into a huge one, it is impractical and if used for the seder , makes it difficult to drink Rov Kos.