I'm considering selling by GK neo 410 to a friend that really could use it more than me right now. If I do, I would consider going the 2x12/1x12 route next time. I have owned a 2x12 in the past with a 500MB. The 410 with my fusion 550 head. I think the 410 fills out a room more, a little more full sounding, but only used that with the fusion not the mb500. Not necessarily more bottom end, just next to a guitar half stack, 410 seems to match up better in a loud rock setting. I realize the fusion plays a part in the fullness/bigness of the sound. But, by adding another 1x12 to a 2x12 would that setup fill in a big way. Or would 4x12 work the best. I'm just trying to decide if I am going to regret selling my 410. The 410 is a version II that have been told is a little more solid sounding than the latest. Running fusion 550 head.