That's not even within hailing distance of what I suggested, deniro.
- Erase your HD.
- Run your 10.6.3 installer.
- DO NOT MIGRATE ANYTHING!
- Select your network during the "Welcome"/setup procedure.
- Run the 10.6.8 Combo.
That will give you a spotlessly vanilla installation of 10.6.8 in which you can see if your font problem is self-induced or a fact of life.
If your new 10.6.8 meets your approval, you can THEN begin updating via Software Update and importing your other stuff to see at what point it breaks.
On the other hand, though, your vanilla installation may display the same font irregularity that you're troubleshooting, and that'll indicate that it's beyond your control.
You're operating on the assumption that something in your OS X installation is breaking 10.6.8, but you've never established that whatever's wrong with it isn't inherent in it.
More: This project sounds like it's been beneficial, so it's in your best interest to complete it, BUT when you finish with 10.6.7, clone it...not just an incremental update to an existing clone, but a fresh one. That way, if you're still unhappy with 10.6.8 when you finally get there you can wipe your HD one final time and import your 10.6.7 clone, and you'll be set until you're ready for a new Mac.
Once, more, good luck!
Forgot to mention that I'm no fan of the App Store either; the best thing about 10.6.8 is Safari 10 and extensions.
