Several things.
Unless you have a certain type of Fel-Pro gasket and you have o-rings, the gasket must always be copper.
2. I know it's done all the time (and no matter how many times it's done this way it's still WRONG) but NEVER EVER run just an o-ring in the block. There should be a groove machined into the head (I always put the wire in the head) and another groove put into the block (aka receiver groove). This gives the displaced copper somewhere to go. If you didn't add the receiver groove they will never seal.
3. How much compression? Unless you are over 12.5:1 and refuse to use studs there in no need for o-rings.
You have a fairly long post without much info.
If the original install was done correctly (both grooves, dead soft copper gaskets, correct sealer on the gasket) and you are still fighting water leaks that use a good block sealer and live with it.
You can take the engine apart and add the receiver grooves if you don't have them, or, just machine the block down and eliminate the grooves. Then order a Cometic gasket that is thicker by the amount that you milled off (for example, if you have a .039 gasket and machine .035 off the deck to get rid of the grooves order an .080 gasket).