There is gdeal's (the late lamented) modification technique on the fd mech replacement 510. It uses a vented screw (available in 10's from Amazon for arount $15). Very leak proof. Adjustable. Not spring loaded. Sticks out a ways. The vented screw is the problem.
He used them in the pico and the gdna. I can't find the links anymore. Probably because he was banned (unregistered supplier).