Multicam Imports & ProRes Behaviour

Latest 10.3.2

For a twincam edit with imported AVCHD files, original media was copied over to the library as expected, creation of optimized media remained unchecked but checked as a demand for multicam clips in the preferences.
The question is how and why is the chosen codec not the same one as the user selected render codec ???

I'm using PR LT for rendering, but the multicam linked creation of optimized files is giving me PR 422 instead.
Where can I control the type of ProRes being used for multicam clips ?

My other problem is having a concluded rendering of a Hawaiki color grading of one camera ( working on a MBP that doesn't allow Color Finale, for lack of a discrete gfx ), the render line/dots reappaear at every new start of fcpx and this library.
Trashed already preferences, still getting the dots and the rendering ( very slow on this mbp ) starts again and again and again .... I can see the library getting thicker everytime.

What's going on inside of fcpx to have such a strange behaviour ?

The multicam preference is 422. There is no selection for optimized media. It's always 422 except for high resolution for formats. That's separate from the render selection. Switch off the optimize preference for multicam and use proxy instead.

Don't know about the second problem. I would switch off background rendering.