RE: Video of "" Saab-Draken "" please? it helps me to find!
I was just looking at some foamy Draken build threads, elsewhere, and they seem to agree that CG should be a little ahead of the "sweep break". One with wingspan of 13" / length of 19.5" said he had moved his CG forward to 1/8" in front of the break and it was pretty good but he was not sure if it was exactly right yet.
(making a flat foam proof-of-concept model seems to be a relatively common procedure among some scratch builders.)