Haynie, there are some different answers on that matter.
As you've probably read from my description, I've took two roads at once:
1) I've chosen lighter wood. Some older, 3000-5000-7000yrs old would be jet black with less pronounced grain, I believe. So with lighter wood I do not have any problem putting oil finish in top. In fact, it doesn't go "on top", it goes more in open pores from brushing, as "hard" wood after being polished do not take much oil or darken.
I will take few older (darker) pieces in days to see how it goes. The source of bog oak I have found have whole lot of different wood, different shades, different grain, different density.
2) I've "brushed" it (sandblast is option if you have equipment). I used soft (much softer then micromesh) abrasive pads from SIA, also had 3M variety same kind, they are also way cheaper then MM, about $1.2 per 5" pad. Sanded with paper to 400grit, then pads 800-1000-1500. "Brushing" effect appears from sanding lengthwise with 800 (can be 600 or even less). I've noticed that effect working with wenge in normal progression (sand with lathe on - stop and sand lengthwise) and on wenge it almost eliminated soft layers of wood if working long enough.
CA finish doesn't look really good, as you can see from my post.