Stupid SPDT throw question...

this should be totally obvious to most people who dont even have the fantest idea about electronics but when it comes to switches im totally dumb unless i have one in front of me with a power source and light. Im looking for a way to have an off and switch between a wall power supply and a custom built dc to dc regulator via a simple two pin connector, i drew this up as a simple example it seems right to me but im just not sure for some reason,

Comments
For the simple reason that I do not trust wallwart adapters, especially when the current draw becomes critical. I would use this setup: