Well, i finally figured out, as i posted it yesterday on twitter, how to make almost perfect conversions, with no eyes popping
Tip is simple : dont touch/move the eyes in blender
move them in the hihead.scne
it can take a lot of tries, but it avoids any popping issues !
note : if you reimport the files in blender, the result i will be strange with eyes hidden in the head, but ingame the result is clean.
Results :