Albertese, you beat me to it! However, since I went in a slightly different direction with my sketches, I'll post them anyway. They are rough estimates at best, but should suffice for now.
I have used Casimiro's & Strategic Design's drawings for the side view. I am also going with Bllsdwlf's research which shows that the TMP-E must have been at least 1,164' in order to fit the giant cargo bay as seen in the movie. As for the TOS-E...well, we shall see:
Matching the upper diameter of the saucer gives us an overall TOS-E ship length of 1198'. You can see the TMP-E "hiding" inside the original shell here:
Bits of the Engineering hull are sticking out here and there, but that is mostly because they differ in shape so much; while the TOS Engineering Hull is a tapered cyclinder, the TMP's is similar to an ovoid barrel. Weird, but I'm sure the Starfleet Engineers had good reasons for what they were doing

As for the saucer, it is mostly a good fit, and the thickness of the rims are almost identical (with the TMP-E slightly thinner). However, the angle of the rim edge is much steeper in TOS, and it would require welding extra girders onto the edge of the saucer to achieve - something I was trying to get away from with my "big Enterprise" approach.
So, what happens if we instead match the
lower edge of the saucer diameters? Well, for one thing we get a TOS-E of approximately 1,235' in length (difficult to be precise because of the curves):
As well as solving the issue with the saucer rim angle, the slight protrusion from the lower Primary Hull is also now gone - the refit hull nestles entirely within the original.
The refit Engineering Hull also fits a little better into the original, but as I mentioned earlier the shapes are so different that a lot of rebuilding must have happened, regardless of the size.
In both examples I am assuming that the dorsal was completely replaced, as well as the bridge & command "teardrop" section. I have orientated the Primary Hulls to the common centre of the saucers, and the Engineering Hulls to the shuttlebay (vertical) and the start of the deflector housing (fore/aft).
But
Egger's original post asked about an official length 1000' refit model, didn't it? Well, if using the examples above we were to match the upper saucer diameter then the TOS-E would be 1,029' long. If we match the lower diameter it comes out as 1,061' which coincidentally is not too far from
Cary L Brown's figure!
I haven't done much on the deck placement with these examples, but a quick pass on the larger TOS-E shows enough space for ten 10' decks, plus the Bridge. The refit would have at least one deck less if it followed the same deck structure (which it should).
(Edit)-
ADDENDUM
One of the reasons I was so strongly advocating a (very) large Enterprise was because of
Cary L Brown's work on applying real-world engineering techniques. It makes a lot of sense to have some bulkhead support for the nacelle pylons and, by extension, for the dorsal too. After
Egger's post I went back and read Cary's thread again - it's fantastic stuff, but I'd forgotten just how intrusive the
dorsal supports are. Even allowing for that, in the end Cary had to just accept what he called a
"TV magic" solution for the place where the
dorsal attaches to the saucer. However I have to wonder - is there any reason why this semi-magic solution can't be used again, say... on the other end of the dorsal? Or on the nacelle pylons? Kirk did ask to jettison them during
The Apple so there must be something similar in place.
Anyway; thoughts on a 1235' Enterprise?