So, after asking yingmin a heap of times for a water test of the piece pictured below and not getting one because he was busy, he told me he only had a few in stock as samples and I could have one for just the price of postage.
I was excited and foolishly purchased without seeing a video. The piece arrived today and it sucks! The return tube from the vortex chamber isn't solid as it goes through the perc so air just goes straight up and water enters the mouth piece.
I'm annoyed at myself for making a impulse buy and I feel a little tricked by yingmin. Whether it was his intention to trick me I'm not sure, he may have genuinely been trying to help me out. I've messaged him to say that it doesn't function properly but I doubt he will refund any money.
I'll still buy other things from him because he is a good seller but want to warn everyone else to stay away from this piece.
Edit: After some back and forth with yingmin I can tell he wasn't being deceiving and he really was being a nice guy. He was unaware that it didn't function correctly. Fantastic communication is another reason I will buy from him again.