Disagree about the value of the single bell front squat.
Once you build to 40-60 sets with a heavier bell you won't be asking what the value is.
I am a little late to the party as I bought IC last week. I did two sessions so far, and I really like it.
One thing that people forget is that:
1 - It's not one squat, it's 30, 40 or even 60 squats.
2 - It's not only a squat, it's a clean, a press and a squat. If you do all this using Strongfirst principles, your quads and glutes should start contracting when you plank at the end of the clean, contract even more during the press (pull your kneecaps up, plank hard), and even stay contracted until you start to descend in the squat (tip I got from Geoff Neupert plank hard before you do a kettlebell front squat), to recontract forcefully when you ascend from the squat.
Accumulate all this, and it's a lot of time under tension.
Of course, if all you do is the minimum contraction required to go through the rep, you will get less of an effect. My understanding is that's hardstyle kettlebell training, so treat that 24 like it's your 1 RM.
For context, my go to squat these days is the Zercher squat. I'm in no way a great squatter, but I did 5 sets of 5 at 205 pounds two months ago, and my practice yesterday had me do a top single at 215, which was not anywhere close to a max. Yet, with 32-36 rounds of Iron Cardio with the 24, I get a slight pump in my legs at the end.
So, even with the 24, there seems to be some effect. I know that "pump" doesn't mean much, but I would expect that there would be some changes to my muscles if I get a pump. Of course, it's not the same as doing a hard set of squats to failure, but that's not the point of IC.
Same with the variants proposed in the book. I can snatch sets of 5 with 32 kg EMOM for 20 minutes or more. You would think that adding a 24 kg snatch at the end of each rep in IC would do nothing. Yet, on my second training day I did exactly that, and that 24kg kettlebell felt way heavier on these snatches than if I do a single 24 kg snatch. Without the snatch, I can do the reps almost continuously. With that small snatch, I took 23 minutes to do 32 reps.
We'll see what results I get. For those looking for ideas, my program for the next few weeks (until all that snow melts and I start playing tennis again) will be:
2 days of IC.
2 days of A+A snatches.
On each of these 4 days, after a quick warmup, start with some Zercher squats and barbell presses. 3-10 singles of each (I superset so that takes less time). Use a weight that feels right. Can be waved, the same weight all along, whatever. This is easy strength. Most of the days, there should be no struggle.
On Thursdays , I go to the gym with my wife as they have a 5$ daily pass special. There, I try to do heavy carries, sled pushing, tire flipping etc... Everything I cannot do at home. Something different every week. The goal is to go hard for 5- 10 sets/reps (can be different exercises: 3 trap bar carries, 3 tire flip sets and 4 sled pushing runs, for example), or 4-5medleys.