I used oestrogel for about one year, with reasonably good results. I also had the stickiness you experience; my regimen was to apply twice a day. I can't answer the technical questions you raise with any authority. I do recall, I think, that the med's instructions indicated one should not wash for a couple of hours, at least, to allow for absorption. The test of the effectiveness of absorption, etc, would be the results of blood tests to ensure the med is bringing your estrogen level to the desired range. Hope that helps.