Zone setting for novices

Over the last 7 years of training with structure, I have seen, in that short time, a lot of the science and prevailing coaching advice change/advance quite drastically - surrounding FTP especially. Whether you are using 3-zone or 5/7-zone training model, the benchmarking around Lactate Threshold - or by proxy, FTP, is necessary to building reliable zones en masse to athletes. The more you train, and take the time to understand the value of different metrics in concert, the better you are able to understand the physiological impact of the work being done in both training and competition. What I am curious about, is how a less developed athlete - who also has less historical data - should be approaching zone setting. Forgive the lengthy post in advance, as I try to put context behind what I am getting at.

I was explaining the purpose/impact of threshold work to newer riders, and I was trying to clarify the overused definition of FTP as “one-hour power.” This colloquial definition does not even begin to explain what lactate threshold is in a physiological way. I was explaining that a person could have their lactate threshold tested in a laboratory, but that does not mean that value translates to holding that wattage for an hour. I explained the limitations of muscular endurance, aerobic capability, and even mental fortitude to execute a one-hour effort at FTP.

I also explained the limitations of testing protocols like the ramp test and 20-minute test, in that a person could actually “cheat” those tests by a high reliance on anaerobic energy systems to sustain a higher execution of power than is indicative of their true lactate threshold. With the caveat, of course, that many of the longer tests are not practical to riders (especially newer ones) due to difficulty in pacing and the subsequent fatigue generated. Much of the information available, including that from Seiler and Coggan, advertises the longer formats - of 30 minutes to an hour - as being superior measures for the reasons I already listed. Fair enough, it’s up to an athlete or coach to determine which test is practical and ideal for their training.

Here’s the crux of my question, and something I really hadn’t given much thought to until I tried explaining these concepts to beginners:
I am not sure what to do with the concept of TTE (Time To Exhaustion). An athlete can have a legitimate lab-tested lactate threshold of 250 watts but might only be able to hold that 250 watts for the first 40 minutes of a one-hour TT, after that, they may drop down to 230 or 240 watts (let’s assume the athlete is well-fueled and properly rested). Clearly, if they held that 250 watts for 40 minutes, it is not anaerobically generated, so it’s a likely validation of that 250 watt LT/FTP. If, however, one were to use that 1 hour TT as a “test,” the FTP elicited would be a lower number - 235-245 watts. I would lean toward the FTP as being 250 watts with a TTE of 40 minutes (which would likely be generated on WKO as well). I would set zones to that 250 watts for the purpose of structured intervals and things are pretty predictable. I would also evaluate whether that TTE is a limiter for goal events and introduce work to increase TTE during the season. An experienced rider will likely have a good sense for RPE/HR match to their zones after years of riding, and could sanity check that FTP value as well.

But… is that the right approach for a novice? A newer rider is likely to have a much lower TTE. It may even be somewhere around 20 minutes. So, does it make more sense to
A. Use the decayed value to set zones and work muscular endurance, aerobic development etc. and target threshold building using 5x5s/4x8s then progressing into sustained efforts to bring up TTE with it?
B. Or, should they use the evaluated higher value - still working those fundamentals - and target threshold with a focus on fatigue resistance/sustainability by working longer FTP intervals then circling back to FTP builders like 5x5s/4x8s to drive FTP up?
Perhaps these are two sides of the same coin, but the read across to other zones is also a concern. 20 watts misplaced could be very impactful - Z5+ especially.

My thoughts here are that folks in their first 3 years of riding often lack the experience and aerobic development to draw the distinction between zone breakpoints and having an effective FTP value that they will not have to question is arguably more critical for them. They are much less likely to be able to make the requisite adjustments. We don’t want them riding VO2 Max when they should be aerobic, but we also don’t want them to plateau by having them working Tempo/SST when we want them to be working threshold.