For long hive with frames construction, 2 things to take care with: what kind of above-hive cover you will use, and how much clearance there is below the frames (and above the frames).
I measured the Langstroth box and used that dimension as the height of the long hive. Oops! It was about 1/8" too short, sometimes - because when a Langstroth deep box is in use, it is set upon a base that gives the frames another 1/2" clearance. So, the best dimension to use for the long hive using deep frames is the size of a Langstroth box plus another 1/2" at the bottom. The bees don't generally draw much burr comb at the bottom of frames; that dimension must be larger than 1/4" but can be as large as 3/4" and the bees leave it alone.
The dimension _above_ the frames matters A LOT. If that is less than 3/8", the bees will propolize (using pine resin - so has the strength of epoxy, but is more brittle) the frames to that covering. If that space between the frames and something solid is greater than 3/8", like 1/2", they will draw out some comb in there, making a mess.
Google "burr comb" and you will see images, if this sounds confusing.
So, you must have an "inner cover" above the frames, and below the lid. It should not be insulation, because that will just get shredded when the frames get epoxied with propolis to that surface. You can use canvas, or smooth cloth - bath towel pieces are suboptimal.

Or you can use pieces of wood, ideally 1x thickness, because you don't want these to warp.
I also recommend putting insulation on the inner side of the lid. In all seasons. Like permanently installed. That's where the bees also need protection from the elements - they lose more than half their heat from the lid, so require extra help there. It can be insulation above the lid too, physics don't care. I use R4 foam, but a nice piece below the lid, and scrap pieces above the lid - if you're not being sloppy, might be better off with more than R4.
I would strongly suggest adopting the _exact_ dimensions from the Langstroth deep box for the top, and the rabbet joint on which the frames sit, or however you are approximating that. I would purchase a box, in fact, or borrow one, to see this dimension in action. It's critical. And now is the time to fix any issues there, rather than after bees are in the hive!
Good luck! Oh and you can check out Michael Bush's website, he talks about using long hives briefly. He used a shallower depth - medium sized frames and corresponding space. I loved the horizontal hive setup, but it takes longer to inspect and I have too many hives now to take my time as much.