The 6000 version libs are gone do nothing for you.
I am not sure if you need the 5000 or the 5000a library's
My guess would be the 5000a because the 5242D is fairly recent.
O and when running your examples the picoscope software must be closed (not running at all)
Ok forget the picoscope software. That would be 400 Msamples total for 4 channels. (picoscope handles up to 250 Msamples) So in picoscope software with 4 channels you get 625 kSamples / sec at 10 sec / division (100 sec total) With the SDK no problem no need for triggers, if I would do it in C++ it ...
Depends of how good you are in hacking but the XML where all the info of the traces is in is in the .psdata file But you need a lot of programming experience to find it and connect the dots. You need to find out for yourself I will not help you with this, because the format is proprietary of picotec...
2 of the 4444 scopes at the same time is no problem.
But remember you don't get 8 channels in picoscope !
You get 2 times the picoscope window open with 4 channels on each screen !
The total number of channels will be 8 but not in program.
As far as I know you have only a 250mV offset in the mv ranges. But there are 2 solutions to your problem. They are only working if the GND of your 5V trouble circuit is not connected to the GND of your PC. Most simple is have a external 5V supply that is stable connect the GND of the 5V supply and ...