Every major style guide prescribes a single space after a period. If modern typographers get into bar fights, it’s not because they’re debating the one-space rule. They all pretty much agree on it. I have also seen a fair number of federal court opinions containing one space after sentences — perhaps as a result of the 25-year old law clerks who drafted the opinions. But I also suspect that more than a few elderly judges are aware of the one-space rule. Although my personal preference is to adhere to the one-space rule, it’s hardly an issue that will cause a party to lose a motion. What the client wants, the client gets!