Peter,
Apologies for not having answered this sooner -- I didn't have notifications turned on, and I only visit these forums rarely, so I only stumbled on your question by accident today.
To answer your question briefly, I don't have a Sente->Tbx workflow.
I use Devonthink Pro Office as my main research repository. It will accept just about any kind of file, you can highlight text in almost any application and clip it straight to DTPO, and it has excellent search tools. Of course, once one has collected the information, one needs to make sense of it, and that is where Tbx is useful (for me). So I tend to conceptualise DTPO as my main data repository because of its capabilities in collection, storage, and retrieval, while Tbx is an analytical tool. Other people will do things differently, but that is what works for me, given the kind of material I collect, and the way I need to work with it (I work in psychology and history -- lots of pdfs! -- and as an aside, DTPO will even OCR a pdf that hasn't got a text layer -- very useful.) There is an AppleScript that will take notes from Sente and copy them to DTPO (
http://www.complexpoint.macmate.me/Site/Sente_6_Notes_to_DEVONthink.html). That was what I was using to get the two programs to work together. Nothing stays still for long in the world of software, however, and I've since moved on to using Papers2 as my bibliographic database (encouraged by a massive discount!)
All the best,
Martin.