Link it to the lowest turnover club and the bigger clubs (including us) moan that they're being throttled and can't compete with European rivals. Link it to the highest turnover club and all the clubs lower down will end up having to spend more just to stay still.
Whichever way you try to do it, there are going to be 7 or more clubs that don't want it.
The best way I've seen of handling this is to link it to the lowest revenue team in the league (rolling average over several seasons), but allow teams to spend MORE if they pay a wealth tax - eg. for every 1M you spend over the limit, you have to put another 1M into a pool that gets returned to the entire pyramid. This means the wealthy can spend, but if they do the rest of the league(s) get a kind of 'catch up' payment.
The debate would, of course, then spread to how much the 'tax' is and how it's shared out.
