Note that you don't get Light pengdra from the light technical dungeon and since the regular light mobs give you mediocre xp, you will be much better off running the first 3 technical dungeons and evolve the RGB pengdras and feed your light ripper without the 1.5 bonus.
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Well, I should really read the dungeon descriptions. Was wondering why I kept getting green pengdras.
Well, at least I have a surplus of ruby and sapphire dragons to evolve pengdras. Now I just need more dragon evo mats