Hi James,
I've just added config settings for the page size in url manager (UrlManagerPageSize) and feed manager (RedirectManagerPageSize).
These settings now exist in the source code repository, if you had requested them a day or so sooner they could have made it into the new release that shipped today.
Note that I moved this thread to the Feature Requests forum as you had posted it in the Bug Reports forum but it is not a bug report.
Best,
Joe