Firstly - sorry to hear about your ups and downs racjen. In terms of absorption I'm sure you know that a single blood test won't really tell you very much and especially about how you are feeling day to day which can be affected by all sorts of other factors.
Re differences in the patches. There is no difference in the estradiol between the patches that i can see - they are all estradiol hemihydrate but the online info on eMC isn't always precise enough and hasn;t always been updated ( I have found this before!). For those interested - Evorel sequi consists of Evorel 50 for two weeks followed by Evorel conti ( for two weeks) and the estradiol is "as hemihydrate" which to all intents and purposes is estradiol.
Re variation between different patch doses. This is an interesting idea but you can't really draw any conclusions from that Wikpedia diagram as there are no data about numbers of women etc. Better to look at scientific papers if you want to look at absorption of estradiol over time (pharmacokinetics). Even the graphs in these vary - because women vary and unless you measure levels in a very large number of women - will not come to a consensus. In any case the spot points on the graph are an average of (who knows how many) women and the scientific papers will show the variation on the graph and/or in tabular form.
Therefore I do not think it is possible to say that any one patch is more stable than any other and in fact there is no scientific reasons why this would be so - so personally I wouldn't worry on that score.
What is different between the two patches though is the size of the patch and the delivery system. As already mentioned Estradot and Vivelle dot have a very particular dot matrix delivery system which enable a particular dose to be provided on a very small patch. All of the other patches are much larger and have a different (standard?) delivery system so that alone could account for the differences you are noticing, especially if you are very sensitive to slight chnages. Maybe your actual steady state estradiol levels are not varying (or maybe they are but this is not reflected in the single blood test you had?) but the way the levels are changing over time might be ( because these can be very variable) eg with changes in temperature of your body, outside etc?
So in your case - given that there are differences in delivery mechanism and size between the two makes of patch, and your sensitivity - yes I would try to stay with the same one if possible (at the dose that you were previously happy with and stable) and then at least you will know whether that is to blame.
For info I change my patch every 3 days although many of them are actually designed to provide a good dose of estradiol of about a week.
Hope this helps and all the best
Hurdity x
