Instead of doing another 20 min field test can I use my 20 min NP from a race I did recently? If so is it still 95% of that?
You can not use 20 minute norm power to determine your FTP. There is too much variable there and you can over inflate with the amount of anaerobic power used. For norm power you can use your peak 60 minute. But for 20 minute power you have to use actual power average.
I went out and did a bit of strava bashing today (a bit of FTFP) on some small 30s - 2min ramps. I rode in zone 2 for the main part during the ride but jammed hard up about 6 short ramps. My NP for the hour was 294w, would you consider that my FTP. Just for your info, I have a decently developed anaerobic system.
Look forward to hearing your thoughts
Yeah you can use your normalized power for a 60 minute effort. The only thing is you do have be to careful to determine if your anaerobic power is over inflating the number. The term people have used is norm power buster.
What in return I would ask you is do you feel like you could do 294 watts steady for an hour? Or even 308 watts for 20 minutes? If you feel like you could then yes adjust your FTP to that.
Without seeing every ride, other workouts or files it is hard to say. But by the sounds of your workouts lately it definitely sounds like you are riding stronger and seeing some of your highest power numbers!
2 weeks ago did 40 mins at steady state at 294w and felt comfortable that I could have complete an hour at that intensity, unfortunately traffic lights halted my ride.
So that sounds about right then.