Nice job you've made of that!

BTW, if you connect PSUs in series, it's good idea to fit a reverse polarity protection diode across the output (not in series), to avoid damage if you accidentally short circuit the combined output. Otherwise there is a good chance you can damage one (or more) of them by forcing it into reverse voltage. Also the wiring to the shunt looks a little thin for 50A, although I'm guessing you won't be using the full current for a while.