Whenever I WILD, it only takes about a minute, because it's in the middle of the night, upon awakening from a dream (not DEILD since this is a few minutes after I move around and stuff)
And It's usually by accident, sometimes it's not, and it would still be around a minute, I've still never combined it with WBTB, so when I do i'm sure it will work.

Eye twitching happens to me rarely, I've never seen HI scenes when performing a WILD, never.
Eventually the dream imagery will form around you while your eyes are closed, you won't have to open them or anything, that will just result in a failure. All though, one time I've had to open my eyes, and I was in a dream bed.