Additionally,
You could use Disc spring washers to keep the pressure even if plastic deforms a little bit.
If you need more control over it, this is another bolt option, you might need to modify the intake to make it happen.
Those bolts reach the bottom and torque. then the pressure applied to the pars depend on the spring, washer, rubber washer you use.
VW valve covers use those bolts to prevent over torque and the pressure is applied by the compression of the rubber washer.