question: Is it possible / safe to use a hydra tube directly after it has been cleaned/rinsed with water?
Yes, just wrap some cloth around your finger and dry the joint and you can go. Wet joint could make a joint lock and it leak a drop of water down the bamboo. If there is a lot of water in the bottom chamber, just turn it upside down 2 times to drain it. If the bottom chamber is just wet, you can use it and it will dry out from the hot/dry vapor going through. You can also vape with some water in it, as long as the water level is not high enough to reach the slits, which could be dangerous as it would leak the water down.
So, in short, you can you the tube with water in the bottom chamber if you can't get the water to run down the bamboo and if the joint is dry.
edit 2: I know I have asked before, but this is an official statement from vapefiend's website: PLEASE NOTE: Using the Evo inverted is not recommended as it can cause over-heating and may damage the unit.
On the official Vapexhale website you find:
CAUTION: The EVO may be inverted during inhalation. However, do NOT leave the EVO inverted for an extended period of time.
So I am wondering - are the international (EU) units different and are not meant to be inverted at all?
Vapefied has got the old version of that caution message, vapexhale updated that message because there was exactly this confusion.
You can invert the EVO, just don't leave it like that when you're not actively hitting. And vapefiend should update that too.
I simply don't get the idea of that silicone-adapter kit?
Silicon adapter is good if you have, for example a group around a table with a lot of stuff on it. Passing around the EVO would be difficult, but you can attach a silicone hose like a hookah, and just pass around the hose (if you have any piece with a joint on the output, like VapeXhale hydracirc 2.0 or HydraBase, both of them are in my video). Or you can connect the EVO to your glass through silicone and then you can leave it as its not inverted and if you pass it around, the vape can stay safely away. Also you get many sizes, so it increases compatibility.