Only difference / addition from Summoner PvE Skill Tree guide is that I have placed a second point into Beckon for the reset on Taunt.
Is chat important to you during dungeons? If not, you could simply leave an empty chat window there. (Or rid of it from your UI completely)
Otherwise, you can use that space to put the most recent tip that showed up on the screen, slightly dimmed to show that it was already communicated in a more forward manner.
My final recommendation, a bit more complex, would be to put pictures of the ability circles / rectangles from 6-man, so people have a visual reference when you mention these abilities. e.g. "Use counter when Minou summons shadow minotaurs" show the rectangle aoe indicator from Minou 6-man