The classic steganography methods you're describing may appear less obvious (for lack of a better term), but they're also easier to break once the pattern is discovered.
Then what you're writing will be functionally indistinguishable from random.
hmm ... but maybe too random, humans are bad at being truly random - the entropy in your period usage will be too high ... perhaps xor the RSA output with a OTP of something 'random' you scribbled yourself on a page ;-)
... seemingly random bits, xored with anything not directly related to the bits in question produces seemingly random bits... There are other ways of transforming a sequence of bits to look less uniform, though.