Thanks.

I didn't have to buy any more laths, but the last shorter pieces by the door were made of lower quality laths that we had to lay aside before. If you have some right sized store-bought standard laths available, I recommend to pay much attention to their quality and handpick them. Avoid any larger knots, cracks and cross-grain pieces. Hold the lath horizontally and shake it some, or rest it on the ground and try to bend it slightly. If you hear cracking noises, leave it. If it tends to "hinge" in certain spot, leave it. If it breaks, well, leave it and make sure the shopkeeper isn't watching. This process will take time, but save you trouble later.

Also, when drilling holes for attaching the lattice together: pay attention to make the template lath as accurate as possible. A yurt will forgive many imperfections, but the khana laths really need to have the holes exactly where they should be.

Yes, our lath holes are about 9" apart, but as I said, if I did this again the distance would be bigger and the whole thing would have less laths and would be a little lower.

Another thing: when planning the holes, keep in mind you need the upper crossings form a V at the top - big enough to seat the roof lath into. You need to realize that the resulting V size will be affected by the width of the laths - the wider they are, the more length you need to keep above the top hole to form big enough V when crossed with the other lath. Hope that makes sense.

As for the initial guess, I've been counting that for a while, then my wife started correcting me, using a different method and completely messing my mind, so I just let her do the math

In the end, she mainly used a triangle method:

1) you get your planned yurt circumference, minus the planned door frame width.

2) you realize how high your khana wall shall be

3) you calculate how long your khana laths must be to form a trinagle (rather a chevron) that will have the height you desire for your wall

4) you calculate what part of the yurt circumference will one such triangle take. Divide the circumference by this number. This will pretty much tell you how many "basic triangles" (as we called it) you need.

5) now decide how many crossings you plan on each lath (drawing a picture of two basic triangles with the "inner" laths helps a lot). Once you know how many laths will fill the triangle in one direction, you should be almost done. You know how many such triangles you have around the circumference, right? So, once you know how many laths you need in one direction, you double the number (as there's the other direction yet) and you should have your magical number. Add something as a reserve and go shopping...don't bother calculating the door area with shortened laths and such. When you get there, you just shorten them.

Hope that helps. I bet there are far more smart ways to calculate this, but this worked for us.