I want to point out the one thing I think is missed. I believe you feel unsafe because of the pin on the nautilus being flushed, like how it caused the issue on the SMPL right? If so, you have absolutely nothing to worry about. That is only an issue when someone is using a mechanical mod that has a direct to battery connection, or a hybrid connection. Basically these mech mods just have a hole on the top where you screw the atomizer in, and the pin on the atomizer will make direct contact with the battery when you push the button on the bottom. An RDA has to have a protruding pin to be safe, while most tanks/RTAs have a flush one.
When you're using a regulated mod this will never be an issue. All atomizers will work fine because the regulated mod has it's own built in connection, rather than giving you direct to battery connection. This connection will have it's own pin that will connect with the atomizer. I also have not read of the 20 having the issues the 50 has, but I have no experience with any of those. I do have a SMPL and a Sigelei 150 (regulated), though so I can see these differences clearly.