Yes for the Davy knot
I've been using the Davy knot almost exclusively for flies tied directly to the tippet for the past year or so and love it. I have yet to have the knot fail (of course it hasn't been tested by any true pigs either) and it's much quicker for me to tie with less waste. I still use the Improved Clinch for any droppers tied off the hook shank of the lead fly, but may start using the Pitzen for that purpose based on the two current threads on that topic.
Fly fishing - it's cheaper than a bass boat!