tent size for 2 inside vs outside footprint

The outside length of the LDis 116". The width without the vestubles is 54". Thats pretty much all the space you really need.
I'm 6' and could possibly use a slightly smaller tent, if I had a need and could find as nice a tent and had the money of course. The 90" inside length is all pretty much usable, especially if using all the guylines.
The TT would save a little space. 50" wide without the vestables and slightly shoter. A well liked tent and seemingly easy to sell.

By my reading of the diagram the Lunar Duo needs an almost 10' square to fit the tent with vestibule extended but really only the interior space has to be flat.

So you are only considering the space of the inside footprint as what you have to find for a flat campsite and the vestibule areas beyond that are not of concern? I am not disagreeing just trying to understand. I often encounter fairly dense underbrush between the trees so finding that 10 ft square can be challenging.

Take a look at the Scarp 2. I find it is spacious for a 2 P tent but has a reasonable footprint (including the fly "footprint").

The vestibules shown in the figure are just the doors suspended by the pole guylines with a dirt floor. Nice, but not always usable. Sometimes there's a tree in the way. Tie off to the tree. With the doors flat, you would need a 4'6" x 9'8" foot print.
The DB has a slightly smaller footprint. I believe the vestubiles are somewhat the same. Don't count their width for the minimum footprint. Again nice, but not needed. I also believe the DB is self supporting using hiking poles, which may make it easier to get a good pitch in a tight spot. Don't own one can't really say.
While I would highly recommend the LD, given your size and that you are sharing with your wife especially in your situation, I'm leaning towards the DR.
It was a hard choice when I made it. Nice tents.
Added Scarp dimensions to upper post for comparison.

Thank so much for the info. Basically all three tents have approximately the same space needs. I think it now comes down to the subtle differences and which ones are most important to you. It use to be I went into the store and bought a tent, used it, and was happy, even with whatever quirks came with the design. This may be another case of "too much information" and " too much time on my hands to think about it". I think it may be more important to get something and go use it. All 3 designs come from thoughtful and reputable companies and making the "right" decision will never be crystal clear.

Thanks again for your help.

If you use trekking poles, I would take a look at the Tarptent SS2. Yes, probably a bigger footprint than the others on your list but it's incredibly spacious for two people. I've spent 2 nights in a shared Hubba Hubba and for my money, I'd rather have the extra space, even with a significant other.

If you don't use trekking poles, perhaps the Double Moment is another option. I don't know… I'm a big Tarptent fan but I just don't think the Double Rainbow is that great compared to the newer options.

Another choice similar to those listed, is a SMD Haven. Similar design to the LD, but a smaller foot print.

Another similar foot print size to the Hubba Hubba is the Copper Spur, which is lighter.

To aid in making your decision, try prioritizing what factors are important to you.

Examples…weight, durability, useable interior space, footprint size, cost, self supporting or not, wx conditions used in, ease of setting up, number of stakes, ect.

Each of the tents listed could be a choice, depending on the list order, and everyones priorities are different.

The LD (vertical walls) is huge inside, plenty of room for gear and elbows. The Haven (vertical walls) is a little smaller inside and lighter.

The HH and CS are self supporting, but usually weigh a little more because of the poles.

The DR side walls taper inward towards the top resulting in less useable interior space.

I've not tried the SS2 or the Scarp, so can't comment on those.

The Double Moment looks cool, but doesn't help you with footprint size.

Another consideration is getting a double hammock (Clark Jungle Hammock Vertex) or two hammocks under 1 tarp. Check out Hammock forums.

The SMD Haven is nice. It doesn't take up much width, but it is kind of long. Over 9' long.

If you are considering the MSR Hubba Hubba, check out the Big Sky Revolution 2P. It has a relatively compact footprint. The interior and fly set up together, which is a little faster and nice in the rain. It also has a version with a "porch" option