focus issues are tough, it could just need a cap kit, it could need a new flyback, or it could be the tube itself. but caps first since they're the cheapest/easiest to replace. the fact that you can adjust it, just not far enough, gives me hope that it just needs some new caps.
As for caps leaking... if what you see is a white goo, that's just glue to keep vibrations from weakening the solder joints and totally normal. I don't know what you're actually seeing but a lot of people tend to assume this is a leaking cap when it's not.
A leaking cap generally has an convex (bloated) top and will leak an oily black substance on the board directly below it. If you see this black residue you NEED a cap kit sooner rather than later as that substance can eat away at the PCB and damage it beyond repair.