The sentences you posted are perfectly fine, but it would be more common to just tell the clerk: "I'd like to get change for this hundred."
He or she will then usually ask you, "How do you want that?"
And you'd reply, "Tens and twenties." (You can specifiy how many of each, saying "Two twenties and the rest in tens," or whatever you prefer.)
"May I get change for this ten?"
NOTE: In Canada, you can ask for $1 and $2 coins. However, in the US, dollar coins are not very widely used, and we don't have $2 coins. So, in the US, you would say:
"May I get ten singles for this, please?"
And you would get ten $1 bills in exchange.
"Good morning" is usually said until 12 noon.
"Good afternoon" until 6:00PM (1800)
"Good evening" until 12 midnight (2400)
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