crispy, I think it's probably jumping the gun a bit to move to oral if you've only tried a 50mcg patch. My levels would be about the same on that...
The thing about oral, is you can't reliably test estrogen at all once you start it. Because oral E is broken down by the liver into metabolites, so when you test you will get a falsely high result due to all those metabolites, which doesn't reflect the estradiol which is available to your body. (It's the same with oral P. We can test women accurately using regular P tests only if they use all their P vaginally or rectally. We can't reliably test women in the UK who take oral P. In the US they have a P test called LC MS P which avoids this, but no where in the UK offers it - to my knowledge, even privately.) So you really don't know what you are getting at all, if you switch to oral.
Plus, you increase the risk of clotting so will come under pressure to get off oral HRT as you get older. Plus if you need surgery, you'd need to stop oral HRT and not transdermal.
As you might know, I'm on 200mcg patches and (now) 3 pumps of gel at night. I will test on this in the new year but I have been on 200mcg patches and 6 pumps of gel - and my levels were 893pmol, so I reduced the gel to get me around 650pmol as that was a little high if I didn't need to be up there. But, before this, I couldn't get higher than 330pmol even on 12 pumps of gel (which was the same on 6 pumps of gel).
Which is all to say, you don't know yet if you can't get higher if you use a higher dose. The most common solution for poor absorbers seems to be a patch-and-gel combo because the two different routes seems to allow for more absorption than just using a high dose of only one.... (as me with the gel).
I get prescribed this from my Newson doctor but my NHS GP is happy to then give me the meds. Which is good as I couldn't afford this dose, privately.