>>2311773I have Rio Singlehand Spey line in a 6 weight that is intermediate sinking, I believe they make it in a floating version as well but it is about $100+ & hard to find (I don't think it was very popular & released a couple years back). However, with a good roll cast/ spey technique it will shoot an absolute rocket with no backcast room. I routinely rip off 50+ foot roll casts as long as the fly isn't too heavy. If you can't find any of that or aren't willing to pay for it (understandable), there are plenty of other options of shooting head lines that will load very easily & shoot a ton of line out once loaded.
Anything that has a taper shape similar to pic related will work (what I use)