Hi Loungfly
You can use just about any line as long as it fits in the holes of the head. I have (had) the tornado plus and have used 2.4, 2.8 & the recommended 3mm line.
After using up the original line, I simply used an original as a length sample and trimmed the lengths. I am up to my 3rd roll.
Ovbiously the thinner stuff doesnt last as long but there is no issue with the curling you get from the spool. The centrifical force straightens it when spinning anyway.

Cheers

gcv