find a way to indicate or demonstrate complex rhythms
"Hammer of Thor," great exercise, but the graphical limitations of the moving tab make it hard to know what complex rhythm is represented. It wasn't until I listened to the track that I understood you were looking for a mix of eights and quarter-note triplets. How about a demo recording with the desired melody only without the background accompaniment. I know there's pedagogical reasons not to supply a demo recording, but there's no other way to indicate the presence of complex rhythms in the current setup.
I think that this could be solved by providing the actual notes, rather than just colored bars. This is done in the piano version, so why not bring it into the guitar version?