Having a system with maximum design temperatures (hot) and minimum design temperature (cold, below zero), what is the best way to access the themal stress range?

Some people's approach is:
(1) W+T1+P1 (OPE)
(2) W+T2+P1 (OPE)
(3) DS1-DS2 (EXP)
T1: hot temperature
T2: cold temperature

Others would change the ambient temperature to match the minimum design temperature and do the following cases:

(1) W+T1+P1 (OPE)
(2) W+P1 (SUS)
(3) DS1-DS2 (EXP)
T1: hot temperature

What is the best approach?