"Paying everyone equally for the same work creates the problem that giant people will fall into poverty and little people will gain massive wealth." That's not really how wealth works. If my shirts cost 17 dollars and <PERSON> shirts cost 32 dollars; he would not be impoverished and I would not be massively wealthy. I admit that there are other commodities that support your point better than clothing does, like different sized housing and different food budgets. But on the whole, unequal cost of living is a somewhat negligible factor in determining who acquires great wealth. Inherited wealth, the ability to leverage wealth to make more wealth, the ability to own factors of automation, and the ability to get paid for the work each of your employees does are much larger factors in unequal wealth.
It is also the case that, regardless of size, intellect and skill will be a greater indicator of a person's productivity and earning power. So the correlation between size and earning power would not be 1-to-1. But in certain industries, it may be the case that larger individuals may be more productive, or may be able to fill jobs that smaller people can't (e.g. a 10-pound person may not be able to cook or serve food at a restaurant that caters mostly for a 3000-pound peoples' crowd, with stools that are 10-feet tall). This minor advantage in earning power could mildly offset the greater cost of living.
It is also the case that America in the beginning of the twentieth century did not have anything close to resembling equal civil rights for all, nor did it have equal income by race, nor equal income by gender. 207
I'm not sure what the ideological stance of your world is, but in a vacuum, it does not need to be more equal than the real world.
However, if the people of your world are actively striving for approximately equal outcomes for people of different sizes, they could take the following approaches...
* Decree that certain necessities like food, shelter, and utilities are a universal right. Take public ownership of them. Remove the ability to price them capitalistically for profit, or hoarded. This can especially apply to real estate, which is not man-made, and there's no reason why it should have ever been something people could privately own. Somewhat applies to water as well, but the treatment of water is a man-made activity.
* Have labor unions that strive to negotiate wages that yield equal wealth regardless of size.
* A lot of wealth in America's economy gets tied-up in corporate assets, bank assets, and personal wealth. For example, American corporations have $1.9 trillion sitting around in cash. Banks own a lot of real estate that has been foreclosed upon with nobody living in it. This is a lot of capital resources that we allow to be hoarded by non-living entities who don't need them; which we could have instead taxed, added to the federal budget, and maybe given back to civilians. In your world, perhaps people of all sizes could write-off various size-dependent expenses on their tax returns, and then their differing needs would be subsidized by the tax code, which would have higher federal revenue than we have, because the corporations wouldn't be keeping any wealth to themselves. 207