I think your best bet is combining the commentary from my sda run (http://speeddemosarchive.com/demo.pl?MassEffect2_NewGamePlus_DLC_Casual_SS_13228), which you'll have to download and switch audio track to track 2 to get anything other than game sound, and then maybe just look at a few newer runs to see what's changed. Also could vary a bit based on what category you are planning on doing and with/without dlc. But honestly I disagree on your first statement, there is very little that you can't figure out by just copying a run. The missions I'd suggest listening to commentary for would be garrus's recruitment, mordin's recruitment, collector ship, derelict reaper and the suicide mission. I think most other stuff is fairly straightforward if you know the optimal (movement wise) pattern to take through the levels, which you can figure out from just watching any run.

If you want, you should try talking to aleck47, he has a decent amount of experience looking into the console version of the game from a speedrun capacity: https://twitter.com/aleck47goesfast

Timing starts on gaining control on Lazarus Station now. Old runs have had their times adjusted to compensate.

Made a video tutorial for the game: