The idea behind IAD tatami is that you do the tatami motion immediately before doing your airdash- so do 236 and then complete whichever way you normally airdash and you should get it fine. One thing you might be missing is the timing on K itself, make sure you aren't doing it too late (usually the case, it's quite fast after the IAD). Also, because it's a special you can get two inputs for the tatami mat by both pressing the button and letting go, so make sure you're tapping K instead of holding it at all (on joystick, double tapping K gives you 4 inputs, but double tapping isn't really possible on pad). For TK youzansen, 623696(3) is probably your best bet, starting at 6 and going down to 2, up to 9, down to 3. Once again, to make sure you're not getting it to early or too late i recommend tapping the button for two inputs, and hitting S asap because when you miss it, it will almost always be due to being too late or missing your motion.
Using pad makes these more complicated inputs significantly harder and slower than they would be on a joystick, maybe you should look into making the switch .
If you're still having trouble with it, look at how you're messing it up, that will be the best clue as to how to fix your input. Turn on training mode input display and make sure you're hitting everything you're trying to hit.