I appreciate the offer, but I need to learn how to deal with him effectively on my own. This was only the first time I fought him, after all. I think the biggest problem is that I keep expecting him to act like rathian, and not stay in the air so much. So it becomes the simple fact I'm not attacking as much as I should be.
I don't block with a GS. I dodge. I find GS much more effective when you're fighting a monster that you don't get to combo to death. For instance, R. Ludroth and Great Jaggis are much quicker to kill with a LS than the GS, even if the GS has thrice the power, I find. Might just be the way I play though.
As for thunder, I do have a Lagiacrus GS, but Sieglinde is 200+ more attack, and has twice the sharpness. I don't think it'd make a huge difference. I just have to try again.