Even just trying to turn one screw without holding the other side down is VERY hard without slippage and there are too many nice polished parts around it lol
I've got to do that on my new watch as well, and I just found out that the tiniest screwdriver that I have, which is used for fixing the mini screws on glasses, doesn't fit the slot for the screws affixing the strap to my watch. To be determined, I might ...
Good luck with changing the strap! I recently did it on my 5707, and may never try it again, for all the reasons you've discovered. (See here .) Meanwhile, this is the second post of yours that makes me rethink the Breguet Marine line in a better light. (...