I can't add much wisdom about the avocados specifically, but I will say that it is important to have a fully cleared upper digestive tract before ingesting harmalas.

Perhaps you need to work with harmalas alone for a while, to discover your response to varying doses and to get used to the physical symptoms that seem to be a more or less unavoidable part of the harmala experience.  Some amount of conditioning and desensitizing may help to tone down the nausea into a less obnoxious feeling of a bloated gut.

I strongly advise to try ingesting dmt and harmala extracts together.  Not doing so is in my experience less effective.  Not combining wastes dmt and requires higher doses of harmalas, with higher associated physical discomfort levels.

Careful and controlled experimentation is a good thing.  Please report back on your endeavors and results.