I've gotten the glitch to work 10 times today, so I think I've got an idea of how to trigger it semi-regularly.
My strat so far has been:
1.- Play on (5,2) of the original adventure map (2 Gohmas with Ghirahim betrayal on Skyloft)
2.- Use Lana with a T3 Summoning Gate with Rupees+
3.- Move towards the Gohma in the northwest area.
4.- Once you get to apprximately this area
http://i.imgur.com/DWDaPfg.jpg , you stop and start spamming C1. Gohma will be lured slightly towards you.
5.- Once you get Argorok, stun Gohma with an arrow, and use the boosted C5.
6.- Ram Argorok against Gohma until it dies.
7.- During the slowmo and until Gohma's corpse vanishes or your Argorok fun ride stops, start killing the mooks that are near you..
8.- If you got lucky, you should max out your rupees.
Here is a .webm of the strat in action by another person who also got it to work
http://webmup.com/QqPWw/
Hope this helps.