Gents, this horse has been flogged many a time before... but let me jump in and offer a few thoughts.
1 - Whatever Chris Spealler says, that might be a good idea to follow. I saw him at the CF Games (he was 4th overall, I believe, by a hair). Whatever he is doing works.
2 - Coach has often said at Certs that the true metric of a workout's "intensity" - in fact the only metric - is work performed over time - or power. Period. End of discussion.
3 - My own personal experience from 20 months now is that there are (at least) two different factors at play, some of which have been touched on, in the two different approaches. "Selling out", in the sense of going to muscular or metabolic failure, comes with a much higher recovery time cost. Some people think it "feels" harder because of the attempt to push beyond muscular/systemic failure limits. It's just that, however - a "feeling". It's perception - the reality, in measurable terms, is how much work was done for that given period of time. "Managing" your workouts is nothing more than listening to your body closely and heeding its warnings that its about to crash.
4 - Some specific "selling out" techniques, however, can help, but I find that they work only when my max rep limit cuts significantly into the total I'm shooting for. e.g. If the workout calls for 40 pullups and I know I'm good for about 25 before failure, I'll do 23 on the first shot because it only leaves 17 for me to "limp" in. I can get that in 5s or 6s relatively quickly without a ton of recovery. But if, like the other day, the workout calls for 50 hspu and I know my max is about 12-14, then I'm starting with sets of 7, maybe 8, and trying to really manage that one, otherwise I'll fail and stil have a LOOONNG way to go.
Ultimately, to answer the question, I think between your hypothetical A and B CFers, you get to where you want to be fastest by maximizing your work output every single WoD. That applies whether it's a 1RM on the deadlift or a MetCon chipper, because those are distinctions that matter only to us and not to the random tasks nature frequently drops on us.