I think you may be the only one attempting to use pkgsrc on OpenBSD, Oko. I've seen no discussion of it on ports@ at all. On misc@, I see brief mention in 2006, and an aborted attempt by one user to use it in 2003...
Marc Espie (the "father" of OpenBSD's ports system) discussed pgksrc, his integration of various features of it, and differences which remain in an interview he gave the NetBSD Project for their "10 years of pkgsrc" celebration. His interview starts here:
http://www.netbsd.org/gallery/10years.html#espie