autotune works off your ego settings. If running msnse, go to basic setting->exhuast gas settings and choose wideband. I'm assuming you have setup your wideband in the configurator.
Then set your ego switch point voltage to whatever is stoich voltage out of your wideband.
For ignition events i use 16 ignition events per step... but you may want to play with that.
for controller step size i have used 5% in the past, and i got some surging on the freeway at partial throttle, backing it off to 3% worked well, and now i run 2% since my map has become better.
controller authority: i wouldn't use more than 10%, but with a wideband i wouldn't be too afraid to use more. (maybe up to 15%)
Then use the active above settings to set when you want MS to go into closed loop mode.
Ok so you probably knew all that... but theres more.
Go to lamda AFR settings, under the "more settings" window. Here you can choose to change your step size % after a certain kpa.
You can also set up your wideband AFR tables.
Once you setup your afr tables, go to the tuning window, click on autotune and go for a drive. Don't forget to hit alt+b when your done to burn the new table to the ecu.
things to keep in mind: the authority*gain is what determines how big the VE table step is during autotune, and gain is .5, so 10%*.5 = 5% ve table jump. The smaller the number, the more stable the jumps will be, but you should experiment with that as well.
hope that helps!
-oliver