You can get a smooth product from a food processor if you are willing to do it in small batches, very slowly (I take around 5 minutes to process 1 cup of nixtamal in my 11-cup food processor, with pauses to scrape it down). I can do that without adding too much water (and in fact I have to add more water after I'm done processing).
I also bought from Masienda; they are indeed great!
I also bought from Masienda; they are indeed great!