You might enjoy the previous thread on Readwise’s Reader and DT:
My answer hasn’t changed much since that thread:
Most webpages etc. just go straight to Reader (using their Safari integration). If I know in advance I want a copy of the page for DT, I will write it to PDF (how I save webpages) at the same time and file it myself.
Non-webpage PDFs go to DT first. I move them to Reader if and when I am ready to read them and if I don’t think I need an annotated copy of the PDF (see note below)*.
I have the “mark as read” setting disabled in DT so files are marked as unread until I manually change them, so I don’t lose track of anything new.
If something I read in Reader is worthy of going into DT and hasn’t already been added, I will do that after I’ve read it (usually this is webpages that turned out to be valuable - I go to the original webpage and print to PDF then).
Reader now supports export of highlighted PDFs, which was still pending when I wrote that comment. But I’ve not actually been using it much so it didn’t change my workflow as much as I thought it would.
I have a little niggle at the moment - I mentioned in the first paragraph that if I know I want to keep something before I’ve read it, I print to PDF in DT at the same time as saving to Reader. This is getting confusing as I’ve had a couple of instances where I’ve duplicated a file in DT (saving it before I read it, and then saving it again after reading). It’s my own fault - I have a tag on Reader for files I’ve imported to DT, but I rarely tag things as I save them, and then I forget. I’m wondering whether to “ban” importing web articles until I’ve definitely read them, in order to resolve this, but I haven’t made a decision yet.
The other issue I have, not really due to either app, is the huge amount of unread reading I have pending 
Reader has over 2000 unread items and DT is just under that currently. DT of course doesn’t care and works exactly the same as usual. Reader however has moments where it hangs, and crashes are not uncommon. I know they’re rebuilding the app to resolve these issues with large libraries, but in the meantime it is frustrating. I have found though that the apps are worse for this than browser, so I’ve switched to reading in browser. It’s not ideal on iPad, but until the issues are resolved it’s preferable.
I’ve also tagged all content in Reader by theme and set up views on the Home Screen to show content by tag. I maintain a view of untagged items waiting for processing as well. In DT, I move files to their correct group, and I found my lack of filing in Reader stressful. Reader’s ‘groups’ don’t match DT exactly as there are things I like to read that never enter DT (and so don’t have a corresponding group), but where they match I’ve identified them the same way for ease of navigation.