I'm really not an expert on this but I wouldn't choose your plan based on the FTP test. You can do whatever FTP test you like (20 min, 2v8 or Ramp test) in place of the suggested workout at the start of the plan.
AFAIK it's more important to be consistent with the type of FTP test you do. If you did a 2x8 before do that - you'll get a more accurate reflection of your power as you're used to the effort required and can pace yourself better. In the long run though TR are going to encourage people to do the Ramp test as it requires the least pacing and has less training stress.
I'm really not an expert on this but I wouldn't choose your plan based on the FTP test. You can do whatever FTP test you like (20 min, 2v8 or Ramp test) in place of the suggested workout at the start of the plan.
AFAIK it's more important to be consistent with the type of FTP test you do. If you did a 2x8 before do that - you'll get a more accurate reflection of your power as you're used to the effort required and can pace yourself better. In the long run though TR are going to encourage people to do the Ramp test as it requires the least pacing and has less training stress.
tl;dr do the Ramp test instead.