I worked with an IBM Business Partner today to setup the integration between Domino 8.5 and Omnifind Enterprise Edition - also version 8.5 coincidentally.
Ominfind was already setup and working on multiple sources of information - Domino was simply an additional source to crawl. The integration with Domino can be over NRPC (requiring Domino libraries to be available to the Omnifind crawler), or via NDIIOP.
While reading the documentation (rtfm - we actually did it) We enabled DIIOP, setup the Omnifing Crawler for "notes" and were able to search and retrieve results. All in about 20 minutes. You could choose to search all nsf, individual nsf, data directories and individual notes views restricted by a simple selection formula.
We also installed the Notes plugin to place Omnifind in the Lotus Notes search bar - this also required editing to notes.ini to point to the Omnifind server. The end result was a fully integrated search across all the available datasources in the lab - with results available in the notes client.
My only question would be the relative performance of the DIIOP method as opposed to NRPC where a customer has a large amount of data to crawl.
The integration was smooth and really quite easy.