Just looking for a few tips on genji's ult, plus a couple of quick questions.

I'm incredibly close to getting all the achievements for overwatch now, with just 3 left to go. Slice and Dice (genji 4k), waste not, want not (reaper 3 kills in a clip) and raid wipe (torb 4k).

Basically in going for genji's achievement he is now my second most played hero in quickplay (after d.va who I finally got her 4k today at level 196). I make good use of the jumping, climbing, normal fire, reflect and dash in normal quickplay, but as soon as I ult it always goes wrong. I've only ever got 3 kills once with it, and usually struggle to get one. (overbuff says i'm 73% rank with him but 8th percentile (rubbish) dragon kills with 1.17 to give an idea)

I'm just looking for tips to get value out of his ult, I feel its a waste pretty much every time I use it and I would have been better not ulting and doing the same thing but with shruikens.

I know obvious stuff like target healers, squishies, avoid sleep and stuns. How should I be moving (limited by console), should I just wait for an ult to pair with, should I be basically swinging wildly near the people I'm targeting and dash to finish, or save the dash?

Side question, reaper. Will I get the achievement if I just tag 3 and solo ult them? I've had far more luck getting 3 in the ult than getting 2 kills in one clip and going on to tag and ult a third or similar tactics.

And torb, do I basically have to ambush them with my turret (and me)? people always notice the turret so fast before I can even think about ulting as I set it up.