It does take the upgrades to be nearly done before a CEO (private) corp will show profit.
Dont try to sell above market price, best price or slightly below I recommend, cash flow being important. Best to make a little every month than lose 2B in one month when nothing sells. Buy the right quality supplies to get a product with output 250+ when the corp is fully upgraded, dont go silly high though. 175 in maybe, 270 out, around that mark I like, but everyone has their own ideas.
It is hard to make CEOs pay at the moment and you'll want to have a lot more corps than 30 before it pays for itself. The way I look at them is to boost my own countries. My CEO corps in my countries means my country gets the major lump of money, country resources used (CRU), and the income tax of its workers.
You should also search the forums about how to do average supply quality (ASQ), where you roughly speaking buy the things with a corp that it uses lots of cheap at low quality and the other things at high quality to average out the supply to what you want. Or vice versa. Fun math exercise for you but personally I cant be arsed with it, I'm a bit jaded having been here too many years!
One good simple saving on supplies is to buy Q120 FMU with your corps. They wont effect the output quality but are quite expensive.
HTH a bit, Crafty