I hope I'm correct to assume that even LH would not dare to deploy their intra European seats on flights to West Africa

I flew FRA-ACC a few months ago, though in Y, but what I saw looked pretty much like the standard (old) LH biz seat installed into the Privatair aircraft. Can't comment whether legroom and seatwidth are exactely the same as on the widebodies, but space should be OK for that not too long flight.