In beam based FEA programme, creating proper elements (node points) is essential.
For vertical trunion, line of action of force is critical. Hence the connection (node) point. As Dan cited, it also depends upon the critically of the system.
I would rather prefer to model trunion with near/far point method on low temperature/pressure water line and use offset element model for critical line such as lines connected to turbine.
In horizontal trunion, moments are rather important (distance from elbow to point of support). You can use offset element method for horizontal trunion also (I haven't used it) but it need validation from experts.