There was a good boosting post buried in the ellay thread by noth1n regarding using the act 4 hell rift in adventure mode. It's not quite as fast as just escorting them through act 1 on torment six but the alts never die so it's less annoying to do since the boosters can sit at the way point and get credit.

Link: http://www.dual-boxing.com/showthread.php?p=389243

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