If you're following the 8:2:1 ratios of castor oil, beeswax & Murphy's, with a tad more Murphy's added after it's melted, and then stirred vigorously, you should be getting the right consistancy.
If you add too much castor oil you'll eventually reach the point where it curdles and never actually hardens up. It will still work as lube, but it will be a mess to use & carry.
Add a bit more Murphy's if you up the castor.
As far as rust preventative, the oils are long lasting and the wax keeps the oxygen off, but I make no guarantees. I keep my bores coated with Moose Snot and check them monthly if they haven't been shot and I have had no problems.
I also use WD-40 after cleaning, followed by dry patches and then a shot of Rem-Oil befoe I lube it up.
Don't use the moose milk as a rust preventative. Too much water in the mix. An alcohol patch after cleaning with the milk gets the bore dried out for a lubing with the snot.
I use more lube on the patch when prepping the bore than I do when lubing a patch for shooting.