Hi Doug,
It is my understanding that ALL changes have to be done in writing through the mail. I am not sure the time frame is 6 months prior to completeion, but am thinking
may be weeks instead of months. I would just call down to the shop and ask, then you will be absolutely sure.
As far as the options being limited to 5... that was for orders going through dealers in an effort to help the shop get caught up (or not fall further behind), not for an order placed directly through the shop (unless it's changed recently).
~dale