It’s pretty forgiving. For example, an S&P500 ETF and a “Total Stock Market ETF” are considered different even though they are 99% correlated. There are lots of

It’s pretty forgiving. For example, an S&P500 ETF and a “Total Stock Market ETF” are considered different even though they are 99% correlated. There are lots of indexes from different companies that track the same thing and I wouldn’t be surprised if 2 ETFs that track 2 different “Total Stock Market” indexes also work (99.9% correlation?)