reciprocating roof

hey folks

hope ye are all flying it!

i have built two reciprocating roofs and both turned out fine, they are structurally sound.
but.... in each of the two roofs the last pole and the first pole are off. By that i mean that the spacing
didnt work out as per calculations. Now yes i know it is round pole timber so it is, in its nature, going to sit how it
wants.

Could it be the fact that although i get the spacing on the wall plate right... could i be geting the tangent of the raft
from the circumference of roof at the top to the wall plate?

or not high enough support pole for first pole? but that shouldn't have any bearing on the tangent/angle right?

there must be a way to get the tangent/angle right?

if i was laptop savy i wouldnpost pictures of the first two round pole builds!

have poles to start wall frames for the next project, my cabin, so i'm hoping to get some more knowledge... from ye

Stan, I assume that you referring to your vertical angle/spacing. If so, then try notching your timbers if you have many or larger diameter timbers so that your intersection points stay level and don't spiral upward. I like notching by drawing a circular saw sideways (blade same diameter as timbers) or angle grinder. Also, leave your Charlie crutch long and angled so that upon inserting your last rafter, you can lever the first rafter upon the second to last rafter as the fulcrum and then shift the Charlie higher-giving safe room to make the last notch.
If you are having horizontal spacing issues, then I suggest throwing away all the math (save Pythagorean for rafter length) and throw up a rim or tire on a central post as a form to precisely form a circular skylight. however, it's trickier to reach the notching/bolting/lashing for the last third with a form up; drop the form at this point before it is permanently compressed into place, and you can jump inside to manipulate the last pole.