Best Test Method and Sample Prep for CF with core

In a sticky thread Entitled: Composite Laminate Samples Lab Test Results The test samples are specific to the product being developed.

In the general case of a carbon fiber composites with a core material, I have two questions about testing that were not answered in that thread.

  1. Are there standard dimensions for a sample that should be used for this type of test?
    NOTE: In posts elsewhere I have seen a sample being tested that is 20mm wide x 120mm long and 1 mm thick. But with a core, the thickness of the sample would be based on the design thickness of the composite. Would this mean that the 20mm x 120mm becomes the width and length for an appropriate test?

  2. Which test method would be preferred? The 3 point test, or the 4 point test?
    NOTE, I have read elsewhere that materials which are orthotropic like composites are tested with a 4 point test where the influence of shear in the displacements is around 15 %, while for isotropic materials, this influence is not significant.

And finally, I could not find in that thread mentioned above the name of the lab that did the tests. Would any materials testing lab be able to do these types of tests on CF samples? Are some labs better suited to testing composites than others?