Strategy for snagging empty row?

I am flying CHS-ATL-AMS tomorrow and the transatlantic leg departs at 8:00pm and is a Delta A330 with 2-4-2 configuration. We are two adults and two children (7 and 11). Right now the seat map shows 4 empty rows or 4 across and the seats on the ends of each 4 are $30 premium seats. I would love to change my seats so my we have two rows of 4 and my children can lay down to sleep, but am worried that it is too risky since people could end up booked in the middle two seats before we leave. What do you think? Should I just wait until we check in to see if available to be safe? Thank you!

ETA: To clarify, I am considering changing my seats ahead of time and paying for the premium seats, not waiting until we get on the flights. I am just worried if I buy the end seats on each row, that people could end up booked in the two middle seats last minute.

If those are chargeable seats, you will also be at the mercy of the FA's.......as some airlines strictly enforce seat poaching after the cabin door is closed. I cant speak as to Delta's rules, as I don't fly them regularily.....I am sure someone else can chime in.

And, that is how it should be, as what you are proposing to do is technically theft.

Actually you have misunderstood. My apologies if I was not clear. I would be purchasing them ahead of time myself now and not waiting until I get on the plane.

What the others above said.

Also, even if the seat map shows the middle seats empty at the very last moment possible for you to purchase the seats, if the flight is pretty full (you need to check the loads on a site like EF or an app like KVS Tool) they might put someone in those middle seats after you've boarded.

No way to really reduce that risk. The problem with flying these days is that they try to fill planes to the brim, and advanced algorithms allow them to do that.

You could always book the seats, and then if they get filled you could ask whoever is sitting there is they want to switch seats. I suppose there is a risk of them saying no,but I don't think too many people would pass up giving up a middle seat for an aisle.

Thanks everyone. As you can tell, I am not a very experienced long haul traveler. I did look up the flight loads and this is what is says, which leads me to believe that there are many seats that are sold but that have been unassigned, but not sure I am understanding it right. So seems like not worth the risk. We will be fine!
J6 C6 D6 I6 Z0 W0 Y9 B9 M9 H9 Q9 K9
L6 U6 T3 X0 V0 E9

ETA: I have just realized that the 9 means there could be more than 9 seats left. Sorry, it is a learning experience for me and thanks for the help.

I'm not familiar with DL fare classes, but if it is similar to other airlines, then seeing YBMHQK all being 9 tells me that the flight still has many seats to sell (the highest digit is 9 even if there are a million seats to be sold in that fare class). If Y was less than 9, then that's a pretty good sign that the flight is near sold out or perhaps even oversold. But these are just litmus tests and not concrete since we don't have private internal load data available to us. Remember, these are not "seats left", but are actually "seats left to sell". And with the major airlines, "seats left to sell" is almost always greater than "seats left".

Are DL FAs strict about Premium/Preferred seat poaching?

I've seen FA enforcement on some airlines like UA, but not on others, like AC.