Are the rates on Schwab better than Fidelity?
Same as far as I can tell. Schwab makes the days actions available sooner to trade on the secondary market.
For those want to make sure of the rate they are getting they can buy on Schwab shortly after the action. You will get a little less only because of the bid/ask spreads.
I normally set up my buys on Friday for Mondays auctions (holiday so Tuesday today).
Can you show how to buy/sell on the secondary market? Today's 6/mo would be a good example. You do a way better job than me.