I believe it's 11nm... I normally just do them until there tight, but don't overdo it as there's a rubber gasket being used as the seal. I've re-used this gasket with some sealant and not had any problems.
Also, I have a PDF Manual for the 1KZT-E. It's only 14mb so if anyone wants it, pop me a PM with your email and I'll be happy to email you a copy!