QTR-Quadtone RIP

Has anyone tested the min allowed custom paper length using roll QTR?

I was trying to save money on tests and used a 4 inch length for the Epson driver; the 
result was 8 inches of a 16 inch wide image. When I upped the defined length to 6 inches 
it seemed to work fine.

But with QTR 6 inches wouldn't work, then I had to hit the road.  Does anyone know what 
the minimum roll paper length is for QTR? longer than 6 inches, or do I have something 
else wrong?

Thanks
Scott