We are lucky that we can adjust to DS's nap times and eat depending on his bedtime. I used to just let him nap late to allow us all to eat together (normally around 6.30) but now he's not always napping, we eat earlier if he hasn't slept.
We do eat together most days and I think it is important that, as much as possible, your DCs eat the same thing as you. There are a few things DS refuses (pizza, oddly) and so we serve him up a suitable alternative while we eat pizza.
There are the odd days when it doesn't work out like that, and I just don't have anything ready for an early dinner if we've been out and DS has unexpectedly not slept, and in that case we might serve him up some quick beans on toast before bed and have a takeaway ourselves later, but I don't want to get into the habit of serving DS only his favourite foods without 'challenging' his eating habits at all. If we all eat together, he often surprises us by eating something he had previously refused. I just make sure that there are at least a few things on his place that he will eat. Sometimes I make concessions to his tastes by serving things seperately that I would normally mix up for DH and I, but he still gets the same stuff.
DH is considering not being self-employed any longer, and in that case we might have to make changes, but I will eat with DS if at all possible. I can chat to DH while he eats, and I don't think he needs to learn anything from watching other people at the table (well, not cutting with the side of his fork might be a good one, but he hasn't learnt that in 31 years so I have given up!)