I just received the 5/8 inch diameter ferrites today and wound a LW and a MW
loopstick. Signal level is approximately 10dB higher than the 3/8 inch
ferrites that I was previously using.
The LW loopstick covers from 90kHz to 580kHz, while the MW loopstick covers
from 410kHz to 2500kHz.
I finished the PC board layout yesterday and e-mailed the design to Palstar,
so I should be seeing prototype boards soon.
This one looks like a winner.

Pete