How exactly do you have your GF rules set up?
I have had good results so far by making 1 rule that include both XBOX's so that way they both have the same priority.
XBL sticky has been updated with the proper way to set up GF rules.
Deleted: easier just to see a screen shot posted in my next post.
On GF set up:
GF and Auto classification should be checked.
Dynamic Fragmentation: Uncheck
Automatic Uplink Speed: Uncheck.
Since you disabled auto uplink speed enter 5120 Kbps if your upload speed is 5 meg. You could even make it 6000 and it wont hurt anything. (1024Kbps = 1meg)
Select cable for connection type.
You are correct about PF that can only work on one Xbox, so don't use it if you game on more than one Xbox. I have PT set up for my two Xbox's and to tell you the truth I don't think it did anything. I will probably have to disable it for awhile and see what happens.
This is the proper way to set up PT for two Xbox's if you are wondering:
The pings you listed seem to be a lot better and probably normal, what do you ping to your local servers? Just go to ping test.net and let it choose the best server. I ping around 100ms if not more to the East coast but I have not checked in awhile and 26-50ms to the local server depending what time or day.
Let us know, we are here to help.