Macro shots from Olympus 60mm, using the Metz macro flash

I was considering the Metz 15 MS-1, too.

How does the flash handle on the OM-D and the 60mm Macro ?

Do you use an additional grip, like the HLD-6?

The 15 MS-1 is attached via the filter thread of the lens, isn't it?

Does that make the combination front heavy ?

Is the filter thread of the 60mm Macro strong enough for the flash ?