Don't expect much improvement in the first 5 weeks...
... but after 8 to 10 weeks the "magic" happens. ;)
Keep the efforts "honest" and work both ends of L5 (from 5 to 8 minutes and down to 3) and complement with some shorter 1minute and 30 second efforts. As much as they hurt, I used to find the 30 second efforts fun. Literally, wind it up as hard as you can and keep it there.
Being totally new to this experience of a higher intensity (apart from experience doing tabata's with a jump rope or running) I did not know what to expect of myself. I have been reading various articles and forum comments as well as looking at the structure that many will do. On Joe Friel's blog he does a 5 minute on 1 minute off, but I knew that would be too hard for a newbie so I opted to try a 4 on 4 off and see how that would play out.
I used the e-Motion rollers with resistance and I have a little bit of trouble dialing into a precise number. Even with the Garmin displaying Avg 3's to help smooth out the view my power output was up into L6 and down to low L5 at times. I expect that in time I will get a better handle on this as it was the same when I first started using these rollers to do L4 intervals.
I ended up doing 6 sets and then cooled down with 15 minutes of L3 and the last 5 at L2. I barely hit 80 TSS, but for these it seems like this is not near as important as the impact of that "magic" you are talking about. Like you say I will not truly experience that magic until later if I am consistent, but from this initial experience I can foresee the magic. It was just an awesome experience. My legs, though my lungs and heart were screaming, felt oddly like they opened up from the experience. As if all the gunk that has gathered from weeks of endurance training was just cleared out. My legs feel absolutely great today as I sit here, but I am sure if I were on the bike I would feel it.
I did not do well as a veteran would do, but I am excited to get started and throw these in once a week. I understand this is an incremental step forward each week.
Here is how it played out on my first experience and as the weeks go I hope to add 5 minute sessions.
All of these scored well into the L5 range
Set 1 - 4 on 4 off
Set 2 - 4 on 4 off
Sets 3 through 6 - 3 on 3 off
I tried to control the effort on the rollers to get to the bottom of L5 and extend the time, but I could not control it so I just pushed hard enough to stay middle or upper range. I think I will get better control as the weeks go by and I adapt.