I finally managed it last night without a Ghorn, with primary burn it's pretty easy provided you keep track of the captains and rotate when needed. Once the first set of mines are sorted your basically home dry, just keep calm and communicate. Get his health down to around the K in skolas, clear adds, rotate to the left platform with the broken wing as its slope. Wait for skolas to reach the middle of the arena, pass the taint then pop weapons of light and nuke the -blam!- out of him with all rockets. Adds will de spawn then you can quickly swap the taint if it's still there and split up to handle mines.