The smallest white lie is intrinsically evil, though it is only a venial sin. But an extremely grave sin like genocide is also intrinsically evil. So the term intrinsic evil does not tell us the gravity of the sin.
The more disordered the act, the more averse to the act we ought to be. But once the gravity of sin becomes mortal, we should have sufficient aversion to never commit the act, regardless of whether it is more or less severe compared to other mortal sins. The reason is that our aversion to sin ought to include a compete rejection of all that is gravely morally disordered. So, once we completely reject a sin, there is no further aversion. Even so, we should recognize that one mortal sin has a greater moral disorder than another.
JP2: "Certainly, from the moral point of view contraception and abortion are specifically different evils: the former contradicts the full truth of the sexual act as the proper expression of conjugal love, while the latter destroys the life of a human being; the former is opposed to the virtue of chastity in marriage, the latter is opposed to the virtue of justice and directly violates the divine commandment “You shall not kill”.
But despite their differences of nature and moral gravity, contraception and abortion are often closely connected, as fruits of the same tree." [EV 13]