It has been a few weeks since I made the original post (time flies when new projects are added). The above posts pointed me to a viable solution (although I wouldn’t consider it ideal) by manually adjusting options 066 & 067 in our 2008 server handling DHCP for the clients booting to the LTSP server. By default our DHCP server points clients to the Fog server. The DHCP settings for the LTSP clients have been manually added to point to the LTSP server.
I would have preferred a better level of automation, but for the time this solution works. Thank you to Vincent & Jaymes for taking the time to help.