You'd probably format it as a percentage of GDP per capita, as it's about limiting wealth disparity (and thus protecting social mobility), distributing wealth growth nationally, and limiting the concentration of financial interest as it's a threat to national and democratic security.

You'd probably want it accompanies by various studies that show that that large wealth disparities are detrimental to social mobility (aka the ability to "work your way up" in classes), and probably some political science papers on the ills of concentrations of wealth.

You'd probably want it to come into force along with laws that limit campaign contributions and big money donors in politics... get rid of that whole "political donations are protected as political speech" crap.... and you'd probably want it as a wealth tax that pays into a sovereign wealth fund with rules on what it can be used for.