This is Elaine, I had checked with my engineer about these problems.
He's quite puzzled about the problem that air leakage from gasket into switch. He said when you stop the switch there my have gas from it for release the pressure. Could you send me more picture or video about this problem?
And for the air leakage, my engineer told me there's some products may have this problem but it not effect the normal use. For the next order we will add copper plate for the nuts(my engineer told me this will prevent ait leakage)and we will provide you 10pcs gasket of each model to instead damage one.
For the connecting rod we will send you new one to instead the damage one.
For the color scratch, I'll ask my workers to put some soft meterial around the tank for during the shipment the scratch is inevitable for wooden case. We had checked the paint before shipment.
For the labels I'll give you more in next order, did you see the stickers I send you extra?
If there's any problem please feel free to inform. we'll try our best to handle.