Very light silicone coating on O rings. Keep everything very clean. Tighten to the point where some moderate effort is required. You can judge approximately from the effort required to remove the yoke. The Allen wrench will require a bit more effort than a larger wrench, but the whole concept is very simple: It's to tighten things enough to be completely secure, but not so tight that the O ring is compromised or so much that it will be difficult to remove later. No magic torque numbers, nothing at all affecting regulator function. Simple stuff. It's not rocket science or the involvement of especially sensitive components. Some folks like to think scuba is some mystically high tech operation. It's not.