Hi @zipit - Thanks again for all your help and guidance with this.
That last code you sent was really beneficial in helping me get a better understanding of how Python Generators work. I've got my Python Generator code working now just as I intended.
Also, creating python tags rather than xpresso is a much more elegant way to achieve what I'm trying to do. I'm guessing that Python Generators might not be the best way to introduce yourself to Python in C4D?
Having used AE for years and utilising Javascript expressions, I'm really excited about what python can open up to me with regards to C4D work.