I see a number of people have viewed this thread and I thought I would share some information regarding the L-600's I recieved from Bruce Morgan, who
Becky asked to help with email's while they are out of town.
I emailed a question about how the L-600's compare to their similar inductance L-500's, and specifically asked if the L-600's are simply L-500's with poles instead of blades. This is Bruce's response:

"The L-600 is an entirely different design from the L-500--it uses short alnico slugs as a combination core and magnet structure, and is really closer to the L-280 in overall performance, with some added richness that two sensing coils per pickup provide"

This has helped me alot. I sent off another question and will post the reply when I get it.