Right (Fig-1)!
Figure-1:
You need to use a PCB layout for this. Many of the professional, specialist in both switch mode converters, and PCB layout engineers I have managed, have taken at least three CAD "spins" to do that. Also they have access to test equipment like RF anionic chambers not normally available to normal mortals working at home.
Exactly how skilled do you think you are?
If your voltage and current are not too high, there are inexpensive programmable buck converters around. In that case you don't even need separate power measurement.
Just set the output current and read the power from the buck.
Ps. you have lovely profile avatar!