I am doing quantitative secondary research on the topic " impact of exchange rates on trading of commodities in UK"

1. using the onion research model what choice should be made for this research and why ? mono, mixed-method, and multi-method research?
2. What research strategy should be used for this research as it is secondary quantitative and five year stock exchange data is to be used
3. Why quantitative approach is best for this research?
4. How much time would be suitable to attempt this research and how?
5. As secondary data is to be collected please elaborate how to collect data ? like I have to find the impact of exchange rates so how would I collect stock exchange data? Hint (More than 100 different commodities are traded on nearly 50 different commodity markets throughout the world. The five most traded commodities in the UK exchange market will be the focus of this research)
6. Data analysis would be through spss please explain its method and what should be the dependent and independent variables in this research please explain
7. what are the ethical considerations in this research?