To place the 柄杓: ready, then R grasps the node from behind, turns it away from you, L supports at the bottom (just release briefly to get around the pillar)
濃茶: 蓋置 goes in front of the 建水, not behind, after the guest has asked for 拝見. The 柄杓 is placed on the 蓋置 like during the 点前
薄茶: Place 茶碗 to the wall, then take 建水 with both hands
During 拝見, the 蓋置 lives on the middle shelf; and moves onto the bottom shelf when you come in with the 水次 (and stays there)
I think it is interesting, because it works a bit like a 台子 or 長板 in that the 建水 is there already.
好み of 仙叟
It's quite nice to use it with a crab, even though then placing the 柄杓 as described above is difficult.
Inspired by an arrow stand, so quite a good one to use for May
表千家 also uses it, but places the 柄杓 facing towards the host.