Hi,
At the moment I have very limited of time...

The solution for the last/first petal problem will be the priority field. It'll be possible to make some petals upper than the others. (Masking is not a trivial solution for this problem, hard to explain)
There's no documentation about Mandala code. It seems that nobody uses it and it doesn't worth to write about it or finish it because 1 or 2 users.
If you look at the included custom tile division code you can find out with some programming background. The code is pascal that compiles into machine code!