A couple of years ago it was recommended to me to keep locators out of a geodatabse. I keep them in local and or network drives. They often reference SDE feature classes or they may reference replicated data in a fgdb located in the same local or network drives. Everything I do is in ver 10.0. I dont have a point feature class nearly that big though.My suggestion is go with what gives you the best performance; one way replication works very well for me where I store and maintain feature classes in the SDE but use them in a fgdb.
That should just about do it....