Potential noob FTP question...
Should you be looking at power to pace it better whilst riding or do it all on perceived effort of 'balls out'
I'm going to presume you are talking about giving yourself a 20min FTP test and it is not your first test i.e. you have at least one previous 20min hard effort where you came away thinking you gave it pretty close to everything you had...
I think there is a danger of setting off too hard if you just go with how it feels, rather than looking at your power readings at the time and trying not to go too much above your previous recent test result. That way, you can always try to go a bit harder if you still feel good when you have ~5mins or so to go, if you blast out a power bazooka early on your legs could be absolutely shot in the final minutes of your 20min test.
For me, I know from from hill climbing on Zwift early this year, that I'm capable of 290W average over 20mins on a good day. The consensus seems to be that you should get better results outdoors, but one issue for me is that we have no steady climbs that take over 20mins for me to climb, I will end up with some flat or even downhill sections in that 20min period (which you can try to keep the power up on, but in my experience it's far harder to put out ~300W on flat or downhill compared to uphill). I try to not go too much above ~330W early on, but it's not easy, if you feel particularly good on a ride.
On Wednesday 15th, I felt unexpectedly good in the legs, so I simply went with feel for the ~10.7 mile loop
https://www.strava.com/activities/1774397290/overview
Last Saturday I got an accidental new best 20min result, while trying to keep to similar power I had done several times up Ashton and Salt, but all the way to Beacon Hill. Even more surprising was I was able to knock out some similar power levels for shorter durations a bit later in the ride too on multiple occasions.
https://www.strava.com/activities/1781297772/overview
I'm still very new to the power meter business, so hopefully more experienced member s will chip in with their 2 pence worth!
Feeling so frustrated about being told by dentist that I should not go out today, even for a recovery ride, when it's almost perfect for me out there in the mid teens and fir bit of sunshine and I've not bit up in the South Downs since Monday... I was very naughty and cycle commuted to work and back today, no way was I going to entertain the bus on a Saints home match day and there being a Pride event in the city centre too!
... Seriously debating going out for a super gentle ride for an hour or so, unless the weather forecast has improved for tomorrow's predictions of heavy rain from ~1000.