The 4" .357 is a fine gun, good choice.
Load with .38 +p if those are allowed.
I think this choice is best for him because he's talking about roaming the jungle as well, where the .357 would be able to be used and be used against attackers with more than two legs as well. .380s tend not to work well on 4-legged attackers.
Then there's the factors of the weight of the gun reducing recoil, and the fact that a gun built for .357s will basically never wear out shooting mostl .38s.
I wouldn't mess with ad hoc reloads, just buy .38 +p.
The accuracy difference really won't matter. .38s out of a .357 aren't THAT much less accurate, and fast-happening gunfights also tend to be close gunfights.
That's just my take on many, many years of .357 use.