MPC constraint vs continuum coupling constraint.

[jball1]

I am working on an analysis of a shaft, which is focused on one particular area. The shaft is a mixture of solid elements (in/near the area of interest) and shell elements. The propeller is included in the model as a point mass, and is simply acting as deadweight at the end of the shaft. Would it be better to tie the point mass to the shaft flange (solid elements) with an MPC constraint, or with a continuum coupling constraint? Thanks for your input.