quattro[Moderator]
18634
For me, your very nice and detailed post
answers your question(s) without the slightest shadow of a doubt, as you are not giving one single reason why you shouldn't make this move. So, what you think about it seems pretty clear to me and it's the only thing that really matters here.
If your Aquanaut has a sentimental value or if, deep inside of you, you fear that you might miss it despite all the greatness of an 1815 Chrono or a Datograph, then don't do it or, at least, wait. Otherwise...
Just my feeling, based on what you wrote.
I wish you the best for your decision.
And congratulations on your wonderful 1815.
Best, Emmanuel