Looking back as a first time builder, "How to torque fluid fittings" has been one of the more confusing questions throughout the build. Information seems to be out there, but it's not all in one place, and some of it doesn't look very authoritative.
For flared tubes with AN-818 nuts, there's table 9-2 in AC43.13, which is for aluminum (and steel) tubing. Pretty straightforward, but it only mentions tube material. Does the fitting material matter? What about 3003 alloy vs 5002 alloy tube?
Then there's AN-924 bulkhead fitting jam nuts. Couldn't find these in AC43.13, but a few VAF threads refer to
this rando link, but is this for steel nuts or aluminum nuts? Unclear to me.
Then there's hose end fittings which are usually (always?) stainless steel. For these, Vans offers a link to
some Aeroquip document for these torque values. Does it matter if the hose is connecting to a steel or aluminum fitting? Lycoming's
Service Table of Limits document mentions flexible hose torque on page 2-30, and includes values for steel and aluminum, but does that refer to the hose end material or the fitting material? Also, the values in Lycoming's document are different from the values in the Aeroquip document.
Then there's the torque vs. flats topic... good grief! Maybe I'm the only one who had trouble finding and digesting all this, but seeing as there are
numerous VAF threads discussing this topic, (with these docs spread all about them), I doubt I'm the only one. I wonder how anyone would do this without VAF as a resource.