Re: Why the Xindi never appear in TOS / TNG / DS9 / VOY
I'm not sure that a table put in technical manuals that the writers never ever actually adhered to counts as "accepted"
There's a table of canonically stated time-distance ratios here: http://en.memory-alpha.org/wiki/Warp_factor
and it's totally random.
Star Trek Imponderables
, fun mashups of Trek's biggest continuity errors! Ep1