
The subject of rhythm is fairly easy in fact and fully based on very simple arithmetic. I dare say that all a rasika needs to know can be picked up in 3 weeks with a metronome. A couple of thanis in different talas, pointing out the parts will do. I am just listing here what I feel should be known.
Basic Lessons for the beginner (all you need is pen and paper) :-
1) Identify musical instruments & learn to use metronome for basics

2) Simple Talas and how to put them with metronome aid
3) Talangas -- Laghu, Dhrutam, Anudhrutam
5) Jaathis and how they affect talangas.
6) Chapu talas -- combined with the basic talangas, the whole recorded repertoire of CM can be followed by this point!
7) Standard Jathi patterns 3-9 counts
8) More complex talas & how to make jathi tala alankaarams.
9) Counting beats and notes in 5 nadais using jathis
10) Counting pauses & combination of jathis and pauses
11) Degrees of speed in 5 nadais using std. jathis with beat speed constant
12) Degrees of speed with beat speed variable and note speed constant
13) Talas in 5 nadais and how the metronome can help
14) 2, 4 and 8 kalais & how to put them
15) Kalai & Nadai Combination
16) Eduppus
17) Eduppus in various speeds and kalais and talas
18) Deshadi & Madhyadi & any other alternative ways of rendering talas
19) Ending patterns -- jathis, swaras, mukthayis
20) Endings for various eduppus and kalais and speeds
21) Sense of tempo
(Side note, we have 6 levels, WCM has 19 ! The metronome software itself can show you the sense of speed of these tempos)
22) Patterns of 3-9 counts & how to derive and sing in jathis (only few examples).
23) Complex talangas -- Guru, Plutam, Kakapadam in various jathis
24) Patterns of 3-9 in 5 nadais, including progressions.
25) Practice tips & ideas, integration exercises.
This is enough to tackle even the toughest pallavis. All credit to AMS Easy Methods and the results it produced with kids and adults alike, me inclusive.
Advanced (We need percussionists here)
1) Mridangam strokes (there are only a few) & strokes of other instruments
2) Parts of a tani
3) Mohras and korvais -- intro on where and how to spot them and types. Korvais are generally identical or arithmetic progressive
4) How to land on an eduppu not on samam
5) Tanis in talas with explanations
6) Explaining fireworks (slow them down with software! They are all combinations of simple patterns!)
7) How people play differently for different types of compositions
More advanced (I might need a pallavi expert here)
1) Basic idea of rubatos
2) Ragam Tanam Pallavi -- parts, arudhi, trikaalam, anulomam, vilomam, pratilomam (right?) and the pallavi tricks.
3) Complex talas -- Simhananda, etc.
4) Two talas in two hands with help of notation
5) Two talas in 2 hands -- different nadais & kalais --- I guarantee that no rhythm in any genre can frighten you now.
6) Ideas on keeping the tala on foot. I came up with my ideas after crossing the Despair Event horizon in a forgettable, unaided violin performance and having hit a wall in my practice. In my opinion, this is the final frontier of CM rhythm.
7) Talaprasthara
Optional
1) Read basic staff notation (seriously, this thing does wonders to exercise your brain cells in rhythm)
The rest is just mix and match of the above and practice. That's it.
In ~30 online videos with notation of a few minutes each, the whole thing can be covered. I don't think the total length of all this needs to be more than a couple of hours. It's enough to give the rasika the tools and teach them how to fish. Let them do the fishing...
What I have observed is that in music classes, the overwhelming majority of the time goes into repetitive practice. Remove this (as in online videos) and put the burden on the student's head, and what you need to know is actually very little. That's why even after years of learning, I still didn't know the basics part fully.
At this point their laya skills will leave others green in envy and they could figure it all out for themselves using the tools they have.
I shall experiment and let you know.