Analysis of spread of data for numerical modelling

Hi all,

I want to firstly admit that I am not the best statistician, hence why I am here, but I will try and explain my problem as clearly as possible.

I am doing a project on numerical modelling (FEA) of thermal expansion. I have three models of different geometries which expand to a specific volume. I am aiming to replicate experimental data so I am changing two parameters (coefficient of thermal expansion and the thermal conductivity) to fit the experimental data through optimisation. From the optimisation for each model I have two/three points which work best for the specific model, for the thermal expansion and the thermal conductivity (See graph).

Ideally I want one unified value of both parameters to use for all three models. So I was just wondering what is the best way to find an 'average' or one value? Are there any specific methods for the spread of data I have?

Please let me know if you need more information

Thanks in advance