Micro Interval Frequency and Duration

I'm really enjoying these micro-intervals (MI) and would like to learn more about how to prescribe them. I race crits and have a sprinters power profile. You can imagine why these have piqued my interest.

* How often can micro-intervals typically be performed during a week?

* How many weeks of micro-intervals are typically prescribed and why?

* Can these intervals effectively replace pure FTP intervals or should they be
combined during the week?

* Should these be performed for an entire season or are they best suited to a
particular period?

* Is it the case that L6 MI are significantly different from L7 MI? Do they
each produce a significantly unique training effect? Should I do both
L6 and L7 MI or is L7 MI sufficient?