Yes, I am saying to get RG to full TM on an easy node. And save him to use only when necessary. And if you use have to use him earlier, then at least try to make sure he ends the battle with good TM, again. If you can't manage that with a retreat or two, then hope you can get him back to full in one of the "lull" nodes before the next storm. That's how I did it when my GW was hard... it is no longer... RG was my key man.
I also have ST Han, though. So I can imagine it is hard to beat the rest of the nodes without wearing out RG.