You'll have a table for 2 - especially as you are Q3.
I reserved the Verandah before the voyage (can do in your account) as thought it may be busy but only seemed about half full; worth it for one evening. $40 a head for the standard menu (there are extras)
Dress: two evenings suits/DJs in a 7 night cruise (we are quire probably on the same one as you, though we've dropped to PG). Others, just a shirt with collar, no jeans effectively, which can just be a polo shirt and chinos (though when I did this I wore a jacket). They relaxed the rules last summer