Advice please: UC A340-600 vs 787

Hello all
I hope everyone is well! It has been a while since I posted my NYC trip reports here (Feb 2014), and since then I had an F flight with BA to the west coast of America, but after being slightly underwhelmed, I am planning to do a similar trip but UC with Virgin.
I've tried to look around the forum for the answer to my questions, but you guys are so full of knowledge and there's so many topics, that I just simply gave up (hoping that flattery will encourage you to help me even though the information is probably already out there!
)
So I was wondering what you would do. In March next year we are going to do a trip from LHR - LAX, and we will be travelling as a family of 5 (my parents, me, my husband and my brother). We have two options for flights on the way out, we can go with the earlier one at 10:10am which is on a 787, or the one at 12.20pm on the A340-600. If you had the choice which would you go for? I am leaning towards the A340 as it would mean having longer in the clubhouse, but I haven't flown on the A340 for a long time and I'm not sure what sort of state they are in/what their inflight entertainment is like. We would be on a 787 coming back regardless.
Also, do you have any suggestions for the best seats for a family of 5 on either aircraft? We were thinking for the A340 8G/K, 9G/K and 10K, but we don't know what we're talking about.
Thank you so much in advance for your responses, and if I have completely missed a topic that is in essence this one, please feel free to link/merge me
I hope everyone is well! It has been a while since I posted my NYC trip reports here (Feb 2014), and since then I had an F flight with BA to the west coast of America, but after being slightly underwhelmed, I am planning to do a similar trip but UC with Virgin.
I've tried to look around the forum for the answer to my questions, but you guys are so full of knowledge and there's so many topics, that I just simply gave up (hoping that flattery will encourage you to help me even though the information is probably already out there!

So I was wondering what you would do. In March next year we are going to do a trip from LHR - LAX, and we will be travelling as a family of 5 (my parents, me, my husband and my brother). We have two options for flights on the way out, we can go with the earlier one at 10:10am which is on a 787, or the one at 12.20pm on the A340-600. If you had the choice which would you go for? I am leaning towards the A340 as it would mean having longer in the clubhouse, but I haven't flown on the A340 for a long time and I'm not sure what sort of state they are in/what their inflight entertainment is like. We would be on a 787 coming back regardless.
Also, do you have any suggestions for the best seats for a family of 5 on either aircraft? We were thinking for the A340 8G/K, 9G/K and 10K, but we don't know what we're talking about.
Thank you so much in advance for your responses, and if I have completely missed a topic that is in essence this one, please feel free to link/merge me
