[TGH-Adfabre]

Lock all national media contracts to the same value.
Set local contracts to the same value.
Set cash maximum to ??? You will have to play with this, a basic guess to me is 1/10 or 1/20 either average payroll or top payroll.
You can manually set ticket prices to close or the same and then there is an option that teams cannot change ticket prices. I cannot remember if that is online only. I think it applies to the AI too.

The result will be the top performing teams will still out earn the poor teams because of increased attendance and merchandising but it will not be so extreme. If a bottom team drafts well and makes decent FA signings they can keep up with the big boys.
Market size, fan interest and fan loyalty will also be important because they play a role in attendance and merchandising revenue.

I have been in a capped online league since 2007. We do not raise or lower our cap. We adjust finances globally to keep financial balance. I would get it all set up and SAVE IT as a template or quick start or just copy the .lg. For the first 3-5 years check finances yearly. Just run through and make sure teams are making money.

I do a yearly financial report for our online league.
I check teams profitable and losing money.
Cash in hand and how many teams had money taken by cash max.
Top player contracts.
Ticket prices. Make sure you go back and check the media contracts.
You will not have to do this permanently, just the first few season and maybe every 5-10 seasons once you get rolling. After you know where all of the screens are and know what you are looking for it takes less than 5 minutes.

Our online league became cash rich and we were seeing demands that were 1/3 of the cap ($30mil demand and $80 mil cap). Over 4 season we lowered cash in the league through the methods above and we are now where we want to be.

God luck,
Tom