I want to mention here a study done by Kligman many years ago: he gave androgen in the form of methyl testosterone (I believe the main dose he used was 100 mg/day, but some of the men got as much as 300 mg/day) to healthy young men and women, and then measured the effect on their sebum production. Surprisingly, there was NO EFFECT on sebum production in the young men, even at the higher dose. The effect in the women was somewhat variable, with some of them getting a little extra sebum, and some of them having no change.
There are at least a couple of possible explanations for such an odd result, and Kligman's own tentative theory at the time was that the sebum production in healthy young men is already MAXED-OUT by their own endogenous levels of androgens, so giving them extra androgen has no measurable extra effect. The sebum production in young women is NEARLY maxed-out (according to Kligman's tentative theory), so their results can vary somewhat from woman to woman.
If Kligman's theory is correct, it would seem to cast some doubt on this whole idea that excessive sebum is an indication that there's too much DHT (or any other androgen, for that matter) being produced by an individual. Maybe an individual who makes a lot of sebum is just a "sebaceous athlete", to use a term coined by Kligman in another study of his, and it doesn't really have anything to do with an unusual androgen production. It might be other genetic factors that are causing it.