Hasselblad 500C + Digital Back Phase One H20

[Amnesialocal]

Dear all,
I hope this thread find you well.
I recently bought an Hasselblad 500C and I'm very very happy with it using it with film, but, due to some rolls lost during the way to the laboratory (minor accidental inconvenient) and some discret cost ( film, development, maybe scanning and contact + post) I start thinking about the possibility to upgrade the gear with a digital back.
Phase one H20 currently is my only affordable type of back I could find around.

I have investigated a bit and I have several doubts that maybe someone over here with all your experience could help me to clarify.

- 1st "possible" issue:
The 500 C and actually the C.Zeiss series C seems from time to time not sincronises perfectly with the back and seems that some delay could happen. This of course give no consistency between the time speed set and the real opening time. I read different comments around, that confirm or deny this first issue. Do someone have some experience/advice to share?

- 2st "possible" issue:
The series C has the focus screen screw in the body, differently from the series C/M and later where the focus screen could be removed with few clicks.
I can't understand if a digital back require change the focus screen or not. The crop mask seems not an issue, as it could be locate on top of the current focus screen ( if I understood correctly). "Theoretically" the focus screen could be changed, but the screws are not just screw but also the way to calibrate the focus. It seems that technical service is required (money). Could someone clarify firstly if it is necessary to change the focus screen and second if this could be done in some way DIY?

- 3rd "possible" issue.
The old backs ( or the ones I could afford) are tethered. With the H20 a power supply connection is also requires. I received really amazing advices by experts of Phase one, and it seems that the pc/Mac need to be connected, and this mean "open". Consequently every time you want to shoot a photo, the laptop need to be open. I'm my case, that I would like to bring the camera with me across the city, this issue could be very annoying. Unfortunately due to software and FireWire 400 tablets are not an option. And also the idea to have a backpack with battery and pc doesn't work because for every shoot I probably should open the laptop.
Any experience/advice on this?

This are currently my main concerns.
If someone over there had chance to try some digital (tethered) back ( fenomenal would be an H20) and could share his/her opinion and advice it would be very appreciated.
I will continue very happy with film, but the idea of having an old 1969 camera update with a digital 16mp sounds very promising.

Lot of thanks in advance and I'm looking forward to hearing from you.

Regards
Amnesia