Experimenting with viscose and tri-lobal nylon

I have become a little disheartened with my wool spinning. I know in theory what I am doing - and have read Mabel Ross's offerings over and over (along with every other book in my rapidly exanding library) - but no matter what I do, I just don't get the result I am looking for. So I have decided to quit spinning wool for a while and practise other materials.

1. Tri lobal nylon - I have both bright white and dyed tri-lobal nylon and have been practising spinning both thick and thin yarns with each. Probably iro 25 wpi and 12 wpi
2. Viscose - Again, I have been practising thick and thin yarns - having said that - my thick wasn't exactly thick. I reckon that the thin was iro 50 wpi and the thick 25 to 30 wpi.

I have been trying to improve my thick and thin yarns as the syllabus requires me to spin thick and thin and consider plies and purpose. The wpi's above were for the singles and by the time they were plied they were much thicker and would represent a range of yarn thicknesses.

I have enjoyed spinning both and am keen to experiment more with these fibres. My main problem is that I need to get my head around spinning for a purpose - and not just spinning because I want to.

So - any suggestions for what kind of yarn I should spin with each and with suggested uses or a project/purpose in mind would be appreciated.

pics to follow