Magnify with MF Assist for macro/super macro with OMD?

I just got my OMD/Nauticam equipment and have a question about using the MF Assist function for close up work. How well does that work underwater?

It seems that with a 10X magnification, the expensive extra viewfinder may not be necessary.

What is the best way to get accurate focus with the OMD/Nauticam setup?

Thanks,

Mark

The x10 thing works great on a tri-pod shooting macro in a studio but is a bit useless in the water where everyone is in motion. The add-on optical viewfinder is the best choice for critical focus and the reason why so many DSLR shooters use them. Keep in mind that once you have made the investment the viewfinder can be moved to any new housing going forward, I have used mine on four different housings to date.