DO-160 indirect lightning requirement confusion
The first thing to appreciate about the DO160, is it is a test procedure specification. When a system requirement states that an LRU is to be compliant to DO160F section 22 (ie the induced transient section), it is expecting a test procedure to be performed on the UUT which is compliant to DO 160. 

The DO-160 outlines the waveforms (Waveform 4, 5a etc), the test levels (1600V, 1600A) and how the test is to be performed. Your system specification should inform you which waveform and the threat level the LRU shall be subjected to since this is dependant on the location within the airframe.

Pin injection and cable bundle are two related tests to validate the LRU is suitably designed to survive a representative environment. Pin injection is to ensure  no damage is occurs under a threat scenario while a cable bundle test is to test for high EM disturbances during a strike event. 

How to design for or validate what is chosen is suitable

A TVS has six key parameters

Ppp Peak Pulse Power. This is the power rating of the devices and should not be exceeded. Take care of temperature derating and design margin de-rating

Ipp Peak pulse current. 

Vwm Working voltage. This is the voltage at which a TVS is guaranteed to to conduct more than the leakage

Vbr(min) This is the minimum voltage the TVS will start to avalaunch the test current 

Vbr(max) This is the maximum voltage the TVS will start to avalaunch the test current

Vclamp(max) This is the maximum clamping voltage at the rated current. 

Working voltage

Knowing the maximum voltage the LRU could be subjected to influences the Vwm of the device (or devices in series) needed. 

Take the 115V bus. The transient worst-case voltage is 180Vrms for 100ms ( 16.5.2.3.1 ) and thus this sets your working voltage at 255V to chassis. 

Source impedance

Knowing the voltage and the current of a waveform is required to understand the source impedance of the thread. Assume the 115V was to be subjected to 1000V/1000A, Waveform 5a. This has a source impedance of 1R. This is required to down-select the TVS's capable of handling such currents 

Knowing the threat voltage, the minimum breakdown voltage and the source impedance, the peak threat current can be calculated

\$Ipk =  \frac{ V_{oc} - \Sigma V_{br(min)}}{R_{source} + R_{circuit}}\$ 

This is a pessimistic maximum 

Clamping voltage

With a pessamistic maximum current known, a representative clamping voltage can be calculate via linear interpolation between Vbr(min) at test current and Vclamp at max current. 

TVS Power

With the conduction current and the blocking voltage known, the Peak pulse power can be calculated.  This needs to be compared against the  energy and the peak pulse power of the waveform.  

How to determine the energy and the peak power of a double-exponential, or multi-stroke. There are a number of ways. One proven way is via the Wunsch-Bell relation where a "K-factor" which is dependent on the type of waveform, is used to approximate teh energy

https://www.microsemi.com/document-portal/doc_download/14639-micronote-120-selecting-tvs-with-ppp-and-waveform-considerations