and how did you setup your scope. Because I tested over here with a 1:1 probe and scope set to +/- 20mV and resolution enchantment to the max. Then I can measure the difference between hanging in the air 90uV and holding it in my hand 194uV. But remember you are measuring in the uV ranges so you won...
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...