Torgue specs for bottle clamps

I had one back when I had some bottle guns. You really just need to tighten it till the clamp stays put and doesn’t rotate.
If I recall on my bottles it allowed the two clamp halves (in the area of the screws) clamped tight to where there was no air gap between them. Bottle diameters vary a lot between bottles.
It doesn’t hurt to put a small dab of anti-sieze on the screws. And remember, the aluminum is soft compared to the stainless screws so don’t get heavy handed with tightening. And tighten each screw the same amount of torque. I rarely use a torque wrench but then I spent my career with all different kinds of fasteners. Only used torque wrenches when customer specified a specific torque requirement.