Hello PaQ!

@You : "...I tend to add one or 2 level of catmull clark...It seems to greatly reduce the continuity problem Michael describe..."

Thanks for the very useful tip!

@You : "...... but maybe it required to much R&D for a single person..."

I think it's nearly IMPOSSIBLE for a single person company.
Some sort of collaboration would be absolutely necessary, but, clearly, this would complicate the "trade matters".

Ciao!