Hi Ashish,
Thank you for the link, that's very helpful.

In terms of CONTSFRI, i've attached a screenshot of the option available in the worksheet:


Based on the link you sent me, I assume for my application using contsfri (frictional stress) is the best option since I want to look at the shear along a surface, then compare those shear stresses and pressure when applying different boundary conditions/ materials. Is my understanding correct?

Sorry if these are silly questions, there's just so many options it's hard to know which is most appropriate without having full descriptions. 

Thank you so much for your help!