I prefer not to get blindsided by an unrealistic request after I've already invested significant time and energy communicating with a potential SB.  So I like to discuss compensation early,  certainly before our first meetup irl.  Lately, it's the SBs themselves who have initiated the compensation talk, very often onsite, with either a veiled reference to a mutually beneficial arrangement, or clearly stating they want ppm, or even mentioning a certain dollar amount that they expect.  I always request that we discuss those topics offsite and give her my text number.  Once we move to text we can discuss specifics of amounts, frequency, etc.  Occasionally the SBs never ask about money, in which case I'll raise the subject myself, gently, by saying I'm very comfortable with the role that $ome $ugar plays in an arrangement.  So they know there's a carrot on the end of my stick!