My plan is to install an L6-30 on the end of the pigtail as that represents the Least Common Denominator plug that locks securely but still supports the power that the charger can draw. I'll then make an L6-30 to 14-30/50 adapter pigtail for plugging in to most dryer outlets, any garage that installed a 240v outlet for a Tesla Model S (i.e. that didn't go for the HPWC), and many trailer parks. There are other outlets that you might encounter and a guy on the Tesla forums has a whole bag of connectors, but I think that 14-30 and 14-50 are fairly common.
The only difference between 14-30 and 14-50 is the shape of the neutral blade and since the Clipper Creek unit only uses 2hot+ground you don't need that blade for electrical power in the first place. If you buy the right DIY plug at Lowes it comes with a replaceable blade for neutral and you just don't install either blade (turning it into a 3-blade plug) and voila - a plug that can plug into either a 14-30 or a 14-50 socket.
