If you are making shooting heads use about 25ft for a 6wt rod, 26-27 for a 7wt, 27-28 for and 8wt, and 28-30 for a 9wt. Start long and cut back a foot until you like the result.

If making a short sink tip to loop to a floating line, make uplengths of 1,2,3,4, and 5 feet and see what works best for your situation.

Slow down you stroke a bit, start the forward cast just before the line straightens out on the back cast, and open up your loop to avoid some rude problems when casting.