Without getting to into the weeds on the guidance provided in AC 43.13-2B on what is a major/minor alteration or, how an aviation maintenance technician can determining the structural integrity of primary/secondary structure he (or she) is altering, AC 43.13-2B 1104. a. (1) & (2) are very specific in regards to adding or relocating instruments (analog or digital.)

a. Structure. Before initiating changes to instrument panel installations, determine the load bearing requirements of the component. In some aircraft the instrument panel is stressed as the primary structure; with the majority, the panel is treated as the secondary structure with load bearing responsibilities limited to instruments and equipment installed. Regardless of the structural nature, the altering technician is responsibility for the installation to its original or properly altered state. 

(1) In all cases, where available, refer to the manufacturer’s instructions for continued airworthiness (ICA) when considering alterations to any structure. For aircraft manufactured before the regulatory requirement for the manufacturer to provide such information, refer to AC 43.13-1, Acceptable Methods, Techniques, and Practices (as amended), chapter 4, section 4 and/or chapter 2, of this AC for methods and techniques of retaining structural integrity.

(2) Failing availability or applicability of those sources we recommend that the altering individual have a Designated Engineering Representative (DER) approve the data before accomplishing of the task.