I've reduced the default threshold from 30 to 20, and this was enough to fix the problem between C3 and C34 you reported. I haven't tested all gates but, if you find others that are closer, add the line and try with 15, or even 10.
Don't use too low values like 1 or 0, because in that case, either you park *exactly* in the middle of parking, or GSX won't know where you are.