maybe more experienced HG managers can tell details regarding revenue.
I can tell you my Homegrown & Locals for 1st and 2nd team:
1st team divII Poland 11 HG players out of 13:
Homegrown & Locals=35 458$ (HG salaries >300k, non HG salaries ~172k)
2nd team divIII Utopia 10 HG players out of 12"
Homegrown & Locals=24 343$ (HG salaries ~285k, non HG salaries ~67k)
Having allstar player can bring +10k for most part of season so being partially HG isn't that much overpowered.
I think being fully HG can bring a lot of cash(tickets, jerseys, HG revenue).....
I also purchased two polish guys(~80k&65k salary) last seasons for 1st team for Locals revenue.
It wasn't big difference(than any other country).
So I would never do that again(it was not that easy to found them, depsite Poland being large community with a lot of players).