I finally got the Manfrotto plate I wanted to use. I'm attatching some photos on how it works, I've been using it for two days and it does a pretty good job, sure needs a couple of seconds more to set up but afterwards you can work on the tripod and handhold without problems and with the camera in any position, the plate holds all the weight of the cable that was on the plug otherwise. It was a luck I previously had the hexagonal head, otherwise I would have had to change.
Anyway I still don't feel very safe, and I won't until someone tells me what really causes the crashes, voltage?, cable?, motherboard?
Arnau.