I would just do some mousing for 36# dacron bulk spools. Don't really know how much you're looking for........... Heck, a 500 yd. spool would fill 10 50 yarders............... .
I took a look @ the fish307 and what they're billing as tip-up line is nylon. In my experience, nylon tends to be stretchy and may rot, wet or dry.
There's lot's of good deals if you're not particular about color. 36# in black has been my standard for ease in handling (line diameter) and ease of keeping track (black color).
/m