I have done several tests through ProctorU with my macbook air (the LSAT and others for classes I have taken) and it has always run smoothly! Just make sure you have enough free RAM to meet ProctorU's requirements
I agree with @leehsaaaa that PowerScore article was a godsend. I hadn't prepared as per the directions of many other writers on various forums, but finding and reading through this article really helped me understand how to properly compose an argu…
As far as I understand, the 20th and 21st are reserved for individuals with accommodations and probably as alternative test dates if you end up running into tech issues/issues with the proctor and require a re-take of the exam.