The Hitchhiker's Guide to the Galaxy has an amusing section on the problems associated with verb tenses when time travel is involved. It has several examples which appear to be constructed for their humorous sound instead of any attempt at sensible rules.
You can arrive (mayan arrivan on-when) for any sitting you like without prior (late fore-when) reservation because you can book retrospectively, as it were, when you return to your own time (you can have on-book haventa forewhen presooning returningwenta retrohome).
This TVTropes page has a list of where this trouble has been dealt with in various media, but none of them (as far as I can tell) are a serious attempt at laying out the rules.
Do you know of any reference where someone has laid out what various verb tenses would even be useful and/or named based on various points of view from a non-linear timeline between speaker and recipient who have experienced time differently?