Just wanted to update you guys on this.
I contacted the pearson exam centre and posted my questions to them. Surprisingly, I was told that I can not even bring my own back support cushion. They said they have one there and I'd have to use that. This is erroneous information as GMAC allows you to carry a support cushion with you. However, there was no point arguing over the phone so I let it be.
I'm gonna print out the list of materials that you can bring with you to use during the GMAT and carry my own support cushion.
For the second question, about doing the test standing up/standing to stretch. I was told that they might be able to set me up in private room but that request has to come through GMAC and I have to go through them first.
Consequently, I contacted GMAC and I got this reply:
"Thank you for contacting Pearson VUE. You may certainly bring a pillow for back support on the date of your exam. However you will not be permitted to stand and stretch during your exam while in the testing room. This may be a distraction for other exam candidates.
For this matter we can only recommend submitting an Accommodations Request. You may view further details on submitting an Accommodations Request via the link below:
Register as a Test Taker with Disabilities
If you have any further questions or inquiries, please contact us again."
They want me to register as a taker with disabilities and given the onerous amount of paperwork required and given that I don't have much time left till the D-day, I think I'm going to have to suck it up and sit through the GMAT. I'd be loading up on pain pills if my sciatica is triggered and just hope they don't make me drowsy.