In practical terms, in today's times, spaces in ellipses have more to do with fonts than with style rules (I used to work in typography). Some fonts have tighter letter-spacing than others. If ellipses look too tight, they will be letter-spaced in typesetting so they are more visible as ellipses, or a word space will be used as a low-quality quick fix. If they are too loose they may be kerned tighter.

A lot of the style "rules" came to be when mechanical typing of manuscripts was the rule. Even in typesetting, in more recent years, before the advent of WYSIWYG programs (What You See Is What You Get), the "copy" (manuscript) would need to be typed by the customer, saved to disk, and the disk converted at the type shop. Whatever way the customer input the copy, that's what would come out in whatever font they had chosen.

In some cases certain character sets will be style-corrected throughout a piece that is being typeset, by a sort of search/replace function, with the kerning or letter-spacing automatically included in the replacement.

I used to proofread manuscripts converted at the type shop-- from customer inputs submitted on disk, to finished, camera-ready product. A lot of silly inputs got fixed by this search/replace method.

But nowadays we're all fonted, and it makes things a bit less rigid in actual practice.

~Susan