I mentioned this before, but what I did was compare my hacked 6.2.3 with a stock 6.2.3 in Beyond Compare. I clearly commented where all the hacks were. I then loaded my hacked 6.2.3 and the stock 6.3 b1 into Beyond Compare. I changed all that was nessecary, paying special attention to the commented hack sections of code.
Starting from scratch and re-adding hacks can sometimes be difficult. In the hack instructions it could tell you to look for some code, but that code has changed in the new release.
The most hair-pulling experiences are when I'm updating my personalized templates, whether for installing hacks or upgrading.
