Thinking about my reply some more, I think your plan is just a bad idea all around. I have the impression you want to benchmark TR’s Base + Build (- Specialty) approach to polarized training. But neither is designed for maximizing FTP. Base might, but Base is just one out of three phases. And one of the main benefits of polarized training is that it raises the tail end of your power curve — also that is not easily detectable with a ramp or 20-minute FTP test. Lastly, I reckon with any sensible structured approach you’ll see improvements.
Personally, I’d just try to improve aspects of your training while maintaining a structured approach as if it were a season. That’s what I did last year and that’s what I am doing now.
For example, if you want to try polarized training, you should find out what a 1-season polarized training plan actually looks like and follow that. @Bbt67 followed a polarized approach with a coach, and he recounted some of his experiences in the Seiler thread and the polarized training thread. He was reluctant to share his training plan, because he wanted to protect the work of his coach, but perhaps he’s willing to share more details if you DM him. One of the things that surprised me was that his coach sprinkled in some Z2 (of 3) workouts every other week.