Never had a problem with a normal clinch.I don't like the improved one as it leaves the tag end pointing forward and just catches more crap from the river.
Like others 5-6 twists lube well and tighten by pulling the tag end.
As far as line to tippet, double uni works for me 4 turns on each side.Real easy knot that can be tied by feel,works good at night.Same goes for the single uni for the fly.