Good luck with your plan. I have not raced mine with NASA, buut this is what I did for vintage racing with SVRA, VRG and SCCA vintage. While yo will not have a passenger, you still may want to consider putting some side protection on the passenger side, and definitely on the drivers side. You cannot control what you may hit, or what may hit you. Even in HPDE events bad things happen sometimes.
Here are some pictures of my roll cage addition to my Superformance 289 FIA. The roll cage was tied into the frame behind the seats and to the hoop under the dash.
The side bars are easy to step over. I have added a second bar on top of the passenger single bar and brought a send bar across from the drivers side to the front hoop.
Hope this helps. Have fun and be safe. Nothing like driving a cobra at speed on a track.
Jim