Hi,
I like Patrick Kelley's method. It does seem to be a stronger transfer with more control. This other guy uses the "open the thumb" method. Hackathorn has his 2-2-2 drill in which he explains his method of switching between strong hand only and weak hand only. His transition method starts at 7:25 on the timeline (video is already queued) but he shares some other nuggets of wisdom throughout the whole video.
Thank you for your indulgence,
BassCliff