Yes, for Writers of the Future, I prefer Courier 12 point font. That's the standard. Now, as little as two years ago, I still took the underline to denote italics, but it is just getting old-fashioned, and nearly all magazines now ask you to italicize the words now.
He'd specifically commented on my use of _underscores for italics_ in his edit of my manuscript, so I asked for clarification to pass on here & elsewhere. It's not the end of the world--clearly not, else I wouldn't be in a position to know this & pass it on--but it never hurts to send in a manuscript in exactly the format an editor wants to read. For WotF: 12pt, Courier, italics