I am sure you have figured this out by now or given up. However if you are still having an issue try the following
LABEL Linux Terminal Server Boot
append tftp:/192.168.24.8/ltsp/i386/vmlinuz initrd=tftp:/192.168.24.8/ltsp/i386/initrd.img ro quiet splash
The above code assumes 2 things.
1. You have downloaded linux.c32 from the syslinux package (I use the one from 5.01)
2. You have extracted linux.c32 to the root of your tftp directory on your fog server (Usually /tftpboot)
Now there are many other factors here, but let me know how it goes.
As for the "Live Disk" that process is much more involved. With a disk of that size it is not wise to use memdisk to boot it. You would be much better off using an NFS share with the contents extracted. There are many post on how to do this especially for Ubuntu. However if you would prefer to memdisk the iso you should be using apache to assist you with this (load times are 5 -10x quicker).