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I've wanted to invent a new spell but need a ruling that would not break the "balance" of the game. Time Warp Fast Forward/Reversed. 11th-13th level, Call it Time Warp: Rewind, giveTime warp: Rewind
Range: Self only
Duration: Instant
Saving Throw: Not applicable
P.P.E.: Special entire P.P.E. base. 150 minimum to avoid permanent losses or 50 P.P.E. minimum and a loss of 1 P.E. and 10 P.P.E points permanently
Level: Considered a 12th level spell
Time warp: rewind is a spell of last resort that allows a second chance to perform an action that the caster deems critical. Since it burns all the remaining P.P.E. of the caster only one attempt can be made and can leave the caster nearly defenseless.
The effect of this spell is to place the caster one melee round in to the past (to the beginning of the last round). The caster will have full knowledge of the intended actions of all involved and will have the initiative. Once the caster does something that he did not do the original time, time becomes fluid again and the caster knows nothing of the actions of others.
Note: A little steep in P.P.E. cost, but I wuz hoping for the same #'s as the FF version-make it more random, & alittle less costly-150 P.P.E. straight.Time warp: Rewind
Range: Self only
Duration: Instant
Saving Throw: Not applicable
P.P.E.: Special entire P.P.E. base. 150 minimum to avoid permanent losses or 50 P.P.E. minimum and a loss of 1 P.E. and 10 P.P.E points permanently
Level: Considered a 12th level spell
Time warp: rewind is a spell of last resort that allows a second chance to perform an action that the caster deems critical. Since it burns all the remaining P.P.E. of the caster only one attempt can be made and can leave the caster nearly defenseless.
The effect of this spell is to place the caster one melee round in to the past (to the beginning of the last round). The caster will have full knowledge of the intended actions of all involved and will have the initiative. Once the caster does something that he did not do the original time, time becomes fluid again and the caster knows nothing of the actions of others.
Maybe base your spell off Retro-Viewing, in other words how far back you can go is based on the level of the caster. However I sense you're not really asking for that; that you've got it pegged and just need #s. Since going back in time gives one the chance to be Omniscient, you might look at the cost of 4th-D Transformation, since that's pretty powerful in itself. Otherwise make it up there in PPE like Dimensional Portal 1000+.
sigh......they get 4-D at 7th......sigh, & it gets a sanity save, 
.
got a copy of TDTMNT handy Gadrin? I envy the old one.Another way to get to the past is to use the Void from the Nightbane: Between the Shadows, book.
A shifter should be able to get there, then with proper armor/protection get to the past -- but of course shunted
to a parallel uni. Find your duplicate in that dimension. Teach him Id Self, AND TELL HIM WHAT HE NEEDS TO KNOW, then return to your future. Then after you leave your duplicate in that parallel dimension summons your past self, tells him and sends him back. Now you have the knowledge you needed to know in the past. It also fits the "Time Travel Chase Our Tails" model, and is screwy
I came up with a variant of Id Self called Gemini Ritual which lets you summon friends you know real well, just like Id Self and makes the process a little easier.
Or pickup TDTMNT which basically specializes in Time Travel and the whole process is much easier. Just need to update it to Rifts.
I also saw a Nightbane site on the web who had an Astral Kingdom which had a portal to the Void. Use the Spatial Mage from Rifter #3 & #5 and do the same for Rifts.