I expanded the time signature to double the original 72BPM such that two bars equal one bar of feel.

No Pushes or fancy stuff needed then, setting the changes to happen on the 4th beat by typing the comma first " ,G"

Here's a link to a short bb file of that Intro:

https://www.dropbox.com/s/zjkl9j7n9nm14k5/SimpleManIntro.SGU

I just used a Simple single strummed Folk guitar realtrack, so it does not accent hard on those beats, you would have to experiment with styles to find that, but the timing works this way. Can't use Pushes in nonexpanded time here because we need that second chord immediately after the Push and pushes work by moving the next chord backwards on the timeline by either an 8th or a 16th note and thus can't play the chord on that beat following, which is needed here.

--Mac