Allo, I was the DM for this, and I had my own input, though I might have trouble putting it easily into words.
Wanted to mirror Miah's statement that this was a lot of fun and very easy from my POV as the DM to run, I was using another adventure meant for OSE as my test for this and it more or less worked swimmingly.
We didn't end up having a beefy enemy battle due to the RP, and if we run into that in future runs of other adventures I'll be sure to note if there are issues on my end. I actually had a concern on the conversion for this, as the "direct conversion of Cairn statistics into grit" had me worried about the skeletal enemies I was using for the adventure, especially since they had outnumbered the party and 5 grit seemed a bit much. I ended up relying on the fact that the fiction of the adventure gave them a clear weak point to attack, and gave enhanced rolls striking for it. But that might have been on me for not accounting for a slightly undersized party.
Otherwise, it went well, the ability for people to intuitively and through the fiction understand what they can do and how they can use it and my own inclinations as a DM were extremely harmonious with the game.
The main thing I'd be thankful for is more of an idea of how to handle treasure and items in the game, especially since once again, trying to convert Cairn's items over causes some issues I don't think are intentional - such as being capable of getting 3 armor (at the cost of it being Bulky and vaguely expensive) if a substantial amount of gold is acquired via buying Plate. Some guidance on what kind of things can be bought and what the general expectations of buying items should be would be appreciated, if only cause armor and weapon purchases have a substantial effect on the effectiveness of the players (which they should!) that I'm worried is unintended.