Hi Jinxed P,
I happened to sit down tonight and read Ajhan Thanissaro's interview with Richard Shankman in Shankman's book
The Experience of Samādhi. I highly recommend that essay - it is incredibly clear and accessible and practical in a few short pages; I wish I could provide the essay to you freely, but that's not possible and it would probably be a copyright violation. Maybe you can order the book or request it from the local library.
Or is access concentration a lower stage (say stage 5)?
Therein Thanissaro calls access concentration "threshold", making the analogy that in going into and out of a house one passes through the threshold. Thanissaro also makes a great distinction (which he attributes to Ajahn Boowa) about how analytical personalities approach anapansati (needing the focus of a small space above the lip and lots of such close engagement) whereas non-analytical personalities take up anapansati as whole body breathing. I experienced this change recently (departure from the lip-nostril area) and was wondering why the body was so pleasantly experiencing the breath. It's been one of the best ways to go to bed in the evening.
I am a little confused about the level of concentration advised to begin insight practice.
Basically, one clear point that many teachers make is that insight and concentration are not separate practices. Another interviewee in the Shankman book describes Ajhan Chah [here I am paraphrasing from memory] holding up his hand, palm forward, and asking his student, "Do you see my palm?" And, of course, the student replies, "Yes". Then Ajhan Chah shows the back side of his hand and he asks the student, "Do you see the back of my hand?" and the student says, "yes". Then Ajhan asks, "When you see the palm of the hand you know the back of the hand is still there, right?" The student agrees. "And when you see only the back of this hand, you know that the palm is still there, right?" Yes. So Ajahn Chah concludes that this how insight and concentration are related: two aspects.
So what are you doing now in terms of practice? Ajhan Thanissaro is near to San Diego, at the
Metta Forest Monastery, if that can be helpful to you.