I highly advise you to read the entire thread that nitegazer just posted, from start to finish.  It is an excellent discussion, with many different and interesting viewpoints.  Here is a link to the start of the thread: Thread for Oral Dosage in Pharmahuasca w/ DMT Dosage Poll

You could combine the harmala and dmt ingestion, but split the dose into three subdoses, ingested at 15 minute intervals.  Or do it like Jees has suggested in an earlier thread, predose about half of the harmalas, followed after some delay by dmt together with the other half of the harmalas.

Be careful with dosing too high on the dmt side.  The experience with the shaman you talk about likely contained much less dmt and much more harmala, as scientific reports seem to point out to be customary in the Amazon.  If you want to replicate that experience, more harmalas and less dmt than you state above are recommended.