That depends on what manual functionality that you are looking for.
I use the Miekon (same as Seafrogs I believe) with a MKll, so others with the exact match as yours may enter comments later, but for now, here are mine.
The Miekon/Seafrogs is a perfectly good entry level polycarbonate housing, I have used mine for several years now. I wish however it accommodated the thumb wheel function. The Meikon aluminium housing does allow for it, and as the housings appear so close in form it does disappoint me that the function is not accommodated. Because of this - I am soon to up-grade to a housing/camera combo with full functionality.
If you are looking for ' manual' focus, it is possible but too awkward - in my opinion - to be practical. 'Manual' control of speed in SP or aperture in AP mode is possible.
I set a typical shooting set of parameters in Aperture Mode and then save it as 1 of my 3 saved profiles - Front Ring set to adjust Aperture - , a second with forced white balance and a third set to Shutter Speed Priority - Front Ring set to adjust Speed.
Then when in a dive and I am doing what ever, and I want to have Manual, I just flip into the appropriate saved profile and I can have full access to select via the front ring. I think having a forced white balance set is useful to then flip on Video - it will then record to that forced white balance - this needs to be confirmed though.
In theory you can also set this up as a Focus ring, but in practice - I - find it too coarse and no where near precise enough. But that could be due to my lack of dexterity - I don't know.
Hope I understood your question, and this is of some help.