What are the ideal ranges for kern.ipc.shm*?

[Chris H]

Greetings,
 Over the years using the xfce4 desktop, I would occasionally receive
SHM ERROR messages. As they never interfered (so's I could notice), I
always put off attempting to track the cause down. However, now having
performed a fairly major upgrade (~1yr since last), The error appears
to greatly affect KDE4 (used to use kde3) applications I run within
xfce4. The windows don't re-draw correctly, and I receive additional
errors,as well:
...
Resource id:  0x0
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x0
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x0
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x0
X Error: BadDrawable (invalid Pixmap or Window parameter) 9
  Major opcode: 62 (X_CopyArea)
  Resource id:  0x0
QCoreApplication::postEvent: Unexpected null receiver
...
After much searching, it would appear to be related to the
kern.ipc.shm* values.
pertinent details follow:
FreeBSD udns 8.4-STABLE FreeBSD 8.4-STABLE #3: Tue Jul  2 13:41:21 PDT 2013
root at udns:/usr/obj/usr/src/sys/AMD64  amd64
with 64Gb ram, and 3 cores, and nvidia-driver-308.88_1.
# ipcs -M
shminfo:
        shmmax:     33554432    (max shared memory segment size)
        shmmin:            1    (min shared memory segment size)
        shmmni:          192    (max number of shared memory identifiers)
        shmseg:          128    (max shared memory segments per process)
        shmall:         8192    (max amount of shared memory in pages)

Thank you for all your time, and consideration.

--chris