tn visa requirements for doing workshop in the us

i have a canadian owned corporation, and am scheduled to do a workshop in phoenix next month. I was talking to a us customs officer on friday and he said i need to get a tn visa as a management consultant (i do have a business degree). from what i've been researching i need to get an 'employer' to write me a letter - i don't have an employer as people have been paying me individually to attend the workshop. so there's not one company paying me, it's a bunch of people. the customs officer said to write that letter coming from my own company - but i'm not sure if that's the best route here? a bit confused as to what specfically i need to do...

You can't write your own TN, so thta is out.

To me this is entry on B1 business visitor.

If it os TN, then the organizer of the workshop should write the TN letter. This would be analogous to being hired by an agency that sends you out to clients, who pay you either directly or thru the agency. The agency would in all cases write the TN.