Hi Pilou

>>How is a reasonable number of polys of an import obj file?
100-200
I think this script will be more useful for subdivision modelling (like Siemens NX).

>>And have you project for that or not ? (Error: N>5)
As I said above, this script supports 3- 4- and 5-sided polygons only.

>>No caps in the result ! Does this normal?
Yes, it's normal. Pentagons isn't supported in fast mode.