I am just doing further experiments with 8 channels OpenBCI + Wiimote + Pylsl (will upload the file soon if still needed)
I read the XDF into EEBLab and am getting all channels, Pylsl and wiimote markers synched in one graph.
I found the matlab examples in labstreaminglayer that use the offset synchronisation
There is github /labstreaminglayer/liblsl-Matlab repo
and the load_xdf.m matlab script:
github /xdf-modules/xdf-Matlab
I guess this script can be just included in the Brainstorm distro.
Regards
Peter