I suggest to start with a simply model (a GLOBAL model) using 1-D CBEAM elements and next compare results using a more detailed model (LOCAL model) meshing with 2-D Shell CQUAD4 elements using the MIDSURFACE of the tube.
You don´t mention the target of the analysis, what results you are looking for, etc... Is not the same to perform a linear static analysis or a Buckling analysis, or a Dynamic Response analysis or a nonlinear analysis, the element type & mesh density is different. Perhaps you only need to know the natural frequency of the structure?.
In any case, always begin with a simplified FEA model, OK?.
If stress results is what you need, then create a midsurface of the tube and mesh with 2-D Shell CQUAD4 elements. The minimum mesh density requirements for a cylindrical surface to mesh with 4-nodes plate elements is to use 6 elements each 90º, ie, one plate element each 15º.