I was having trouble angling my speakers after I set them up in the default equalateral triangle. Heres what I did to finally get it right.

First get the speakers centered.
(Play a song but play it in mono so everything should be coming from directly infront of you. Move one speaker forward or backward until the song sounds like like its coming from directly in front of you when you where you usually listen)

Next angle the speakers
(Keep the song in mono. Now istead of just randomly turning your speakers in and out until you think it sound right, cover your left ear with your hand. Keep looking straight forward. Now angle the right speaker so that the sound seems like its coming directly from the center of the right speaker. Repeat for the left speaker with your right ear covered. Remeber to keep your nose pointing towards the center when listen for where the sound seems like its coming from, otherwise it wont work)

After doing the this my speakers sound balanced like they should. Maybe others already know this but hopefully it helps someone with the same struggle I was going through.

Oh yeah another thing that helped me set up the equalateral triangle was multiplying the distance from me to the speakers by 0.87. This will give you how far apart the speakers should be from eachother. When you measure the distance from your listening position to the speakers you want to measure staight ahead of you to the imaginary line between the left and right speaker. So measure to the center of that imaginary line. Then multiply that number by 0.87 to get the distance speakers should be apart.

Let me know if I you disagree, but these worked well for me :-)

God bless!