ACH is fine. Wire is just if you’re in a hurry.

Not sure if it matters, but I always initiate the transfer from the receiving account. One, you can’t screw up where it’s going. Two, for interest purposes, I notice it shows the full amount in the account right away, even if it’s not “available” for 5 days. Not sure if interest accrues from the transfer date or available date, but either way, I like seeing that it’s there.

Pull funds, don’t push them.