Of the ones you listed I would use the flying dragon, but I like blues so clean gritty distortion is what I like. How much gain do you need? If you're playing hardrock/metal you'll need more.
If you're considering clean boosts, check out the Keeley Katana, I keep mine on all the time. Then there's the Xotic RC booster, and the MI Audio Boost n' Buff, which is a clean boost or Treble Booster, and acts as a very transparent buffer when bypassed.
And I'm with ModNUB on the Danelectro Transparent Overdrive. Check one out. They're so cheap I almost want to buy one for you, 😉 and they sound better then most $150+ pedals I've owned. But they still don't have a lot of drive, but if your amp is just on the edge it will work perfectly!
The Dunlop fuzzface is cool, but if you're gonna go the fuzz route the Keeley Fuzzhead or MJM London Fuzz have more clean output and could push the front of your amp harder. Also the Zvex Fuzz Factory has lots and lots of output, it could really push your amp hard.
The DS-1 is cool, you should use it too, it doesn't matter if kurt or anyone else used one, so does Eric Johnson and Joe Satriani, and John Frusciante. Gain staging is a big part of having good tone. I've got 4 different overdrives on my board, plus one fuzz, and one clean boost. All of which I use in different combinations to get different amounts of gain and boost from my amp. Using two or more drive pedals together can really push an amp hard. Try rolling the drive and fuzz back on your Fuzz Face and your DS-1 and boosting the level knobs to max, use them both together in front of the amp and that may be all you were looking for.
