Hi Emmy,
No problems so far with the little changes to the hack.
We just moved our site from NY to Dallas and changed timezones in the process. I just changed the vB offset from -5 to -6 and everything still worked. Post times are still correct for GMT. No changes needed for 'user cp'.
I dont know how relevant the fact is that our site uses GMT as its timezone, all I can say is that the hack now works perfectly for our site