Wilshire 5000 or SP500?

Hello, first time on this sub.

I'm doing a high school math project for IB where I'm looking at the effects of inflation on the stock market. I researched and narrowed down to Wilshire 5000 and s&p500 as the two indexes that best represent the overall American market. Which one should I choose? I'm thinking of Wilshire because it covers more companies but sp500 is well known and has the larger cap companies. Would it make a major difference as to which one I choose?

Any insight would be helpful here.