That worked! I have a couple of don't fall 10 stories roof tiles from when I was building it, you can ignore those. Its still not a perfect cone, I had to elongate it one 2x2 tile to get it to really work, but its smooth and near perfect and close enough to centered that you can't tell without counting pixels. Interestingly, these are 45 degree slopes until the top, the 26 degree cap piece (x2) perfectly fit to close the holes and blend into it.
Thanks all! With this, I just need to repair rain damage & start moving in...
The dip at the bottom isnt an imperfection, its the minaret roof.

https://steamcommunity.com/sharedfiles/filedetails/?id=2800240620