So, I am currently re-reading the strong endurance manual. And I recall a line from Q&D, 10x10 deliver. But they can be improved upon.
It would seem that the way these would stack up against each other is that template 18 would concentrate the stressors during a series. While template 17 would not concentrate it in that way, it may allow for a greater amount of total work, because the stressors would be more evenly distributed across the session.
I would start with 17 for a couple weeks, and then try 18 format to compare. Now, Especially if you're test driving the protocols for differences, dial down the volume and up the rests as much as you can, to start. Be attentive, and take notes.
My guess, from some experience with sampling other templates is that bigger volumes under template 17 will become a uniquely valuable session, and moderate volumes under template 18 will be uniquely valuable sessions.
However...
In my experience the repeat methods have panned out better for me so far. I think that's to do with my young training age, and my body's ability to tolerate the loading during the session and recover from it afterwards. I believe that in time the interval methods will shine. But, that'll be in correlation with my further development.
So, I'll suggest that as to the mere total volume (under either format), as a dose to elicit a response; it is not always obvious which will work for you. The way it's packaged in sets reps and series, will also make a difference in how it fits into where you are now and where you're headed, and it is up to you to gauge it.
Do you take a big gulp of very intense work and allow it to dissipate? Or do you take smaller bites of less intense work? I bet if you equalize the protocols for overall density, and volume you still end up with a unique effect.