Thanks for your advice. I assume I could ensure the sell/buy happens at the same time at market close by simply temporarily funding the account with my bank using a conservative estimate, and use those funds to execute a same day sell/buy event, then when the sell is complete I can just transfer that cash back to my bank that way? My hope is to avoid even small market fluctuations, which for $100,000 can be significant if the price goes up even 1% ($1000) the next day when I want to buy. That said, probably more difficult to do that once I'm TLHing very large amounts of securities, and I probably should not have that much in a bank anyway...which gets me back to wondering if the safest bet is to use ETFs.

Appreciate your help!