After a first look at the IIT (OPCW) report, I have to say that it looks like a rebranding of old evidence to construct a somehow halfway credible narrative.
The opus revolves around the assertion that the SAA wanted to reclaim territories that it had lost to advancing HTS.

And while the SAA concentrated mainly on Aleppo, 6000 HTS fighters and suicide bombers had gathered north of Hama to launch a major offensive (see dotted line). https://en.wikipedia.org/wiki/Hama_offensive_(March%E2%80%93April_2017) Why Assad decided to use Sarin, but not against the 6000 fighters remains questionable.

At the time of the alleged Sarin attacks, the SAA had retaken most of the lost territory. After that, this line remained almost unchanged for two years, probably because of other priorities. The strategic benefit of a sarin attack on a field is therefore highly questionable.

The smoking gun among the 3 examined attacks is 24 March. Remember: There is absolutely no proof, no photo, no tweet, facebook post, no article, neither from the White Helmets nor from Nusra or HTS nor any doctor or private person. Not even Higgins' reward could change that.

Even more amazing is that after the alleged attacks of March 24 and March 30, countless articles and interviews appeared, but no victim, no doctor, no article, no tweet - nothing and nobody - mentioned this March 24 Sarin attack. On the contrary:

No one had ever heard of this alleged sarin attack until the OPCW March 30 report on November 6, 2017 mentioned that it was heard during the interviews.
It should be noted that this report showed two pieces of evidence which are now attributed by IIT to 24 March. What???

In November, not even Eliot Higgins suspected that 200 litres of sarin were supposed to have fallen over the southern rim of Lataminah on 24 March. And so in October he still expressed a theory which I share. If 24 March happened as described then it would have been a massacre.

After the OPCW report, however, Higgins hastily rowed back. How could it have been a 'false flag' operation if nobody talks or writes about it?
Interestingly, the IIT report coughs up Eliot Higgins' argument. Coincidence? Certainly not.

It's a circle of certain people, I fear.

However, the March 30 OPCW report left no doubt as to where the listed evidence was found. The search field covered an area 500-700m south of the city limits.

However, the March 30 OPCW report left no doubt as to where the listed evidence was found. The search field covered an area 500-700m south of the city limits and included two craters 25-50cm deep. Both craters could not have been caused by conventional aerial bombs.

Now the IIT report publishes the photo of evidence 04SDS(B) / SDS28. It seems that this photo shows for the first time the flat small crater 700m south of Lataminah up close. The IIT report gives no further details but there cannot be more than two flat craters. The IIT says why.

So IIT experts believe that in a war zone with experienced fighters, nobody can simply put 3kg of TNT on the ground. This means that these two craters are - for lack of difference - not fake and therefore both of (likely) M4000 sarin bombs.

But both craters were assigned by the OPCW to 30 March and furthermore - if my assumption is correct - the 04SDS crater is located in the opposite direction from the other crater than the 24 March crater should be.

The IIT cropping does not allow to be certain. So let's assume that 04SDS was found further north than claimed in the 3/30 OPCW report and we are dealing with 3 small craters and no big one. Strangely enough the heavy tip of the bomb lies next to the hole. How does that work?

The Russians would have been looking for this bomb spike at a depth of 4 to 8 meters. Here, the heavy massive tip is just beside the hole. And all the pieces of at least three craters together make exactly one bomb. No part is double.

Of course, the IIT relied on testimony from witnesses who, according to the OPCW, nobody saw anything of the actual air raid. But witnesses later saw a crater filled with a bubbling liquid. That has to be the 04SDS crater, doesn't it? No? Are there 4 small craters?

And then there's another 'evidence': lubricant in the crankcase. It seems the IIT is saying that this clutch would've been lubricated if it wasn't for and shortly before mixing sarin.
But wouldn't you lubricate a clutch at manufacture?

Sorry to say that but the argumentation is completely nuts!

A similar argument concerns the two filler caps. They were screwed on, which was probably very difficult because of the corrosion. And then they found the same sarin in the threads. According to IIT, this is evidence of the actual use of the bomb. Is that so?

Wouldn't you fill the binary precursor chemicals into the opened lids and close them before mixing so that no sarin can escape?
But if these caps are not tight enough, why should it be different during a false-flag operation (assuming they weren't already completely rusted)?

The only argument left is the allegedly unique composition of the chemical. ...which only Assad can possess.
And which was apparently found on bomb fragment 04SDS in an absurd position 200 meters against the wind of the remaining bomb fragments and involved in two incidents.

With all due respect, I'm not convinced.

Is it equally likely that a vial of sarin was lost or stolen during the destruction of the stockpile? Just asking.