A few people I can think off completed the IMC training and passed the test in less than 20 hours. One guy did his in 12 hours.
I did about 20 hours taken over 6+ months, some of this time 3 ish hours was spent in the hold at my request.
I found rant very useful after a few hours. After the test I relised how good my two instructors were as my training far exceeded the requirments for the test.
JL....