John, I thought of you and this post today when I was chasing a growth ring. Hope it's OK if I add some pictures.
Light is so important to this process. The best lights I've found for inside the shop are the 500watt harbor freight shop lights. Sometimes, only a little move of the light makes a big difference. Here's my setup:
I normally run just 1 light, they're pretty hot. This bow has pretty tight rings and I had a tough time seeing them. Looking at the bow from my vantage the ring boundary is tough to see.
Just turning on the left light instead of the right one changes everything.
Don't be afraid to move around the stave and/or move the lights around the stave.
That knot came out pretty good.
George