Divisions of FTL Speed

As is common knowledge to anyone with an even barely functioning physics understanding nothing with mass in the real universe can accelerate to faster then light in a vacuum. This is often paraphrased as "nothing can go faster then light" which is not technically true; there are circumstances where you can slow down light in a medium to the point that other things can accelerate past it, there are theoretical particles that are always faster then light, and things that are completely immaterial like say thought, are not necessarily bound to the speed of light. However there is no physical quantity known that can accelerate to faster then light in a vacuum.

In fiction there are obviously entities that can travel much faster then light and so we must define their speed as being faster then light. However if we are to give them abbreviations to quickly reference speed then it becomes a problem if we are giving characters of rapidly different velocities the same speed category since that would be defeating the point of giving them a speed category. The only differentiation that is regular in versus communities however are FTL and MFTL (starting at either 100 or 1,000c depending on person and context). I wanted to propose a sort of easy way to differentiate speed at very high tiers of speed.

FTL: Same as Normal. Anything above the speed of light
MFTL: Same as Normal. I treat it as over 1,000c.

And here is where the divisions come in.

MFTL+: A denotation of being to lightspeed what lightspeed is to humanspeed or in other words it is 299,972,458 (the speed of light) squared equating to approximately 300,000,000c (slightly less since light is 299,792,458 meters per second, so it would be actually 299,792,458c) or above.
MFTL++/MFTL(2): A denotation of being to MFTL+ what MFTL+ is to lightspeed, so multiplying that by another factor of c's velocity. Slightly under 90 Quadrillion C and above
MFTL+++/(MFTL(3): The Trend continues. Approximately 26.944 Septillion C and above
MFTL++++/MFTL(4): The Trend continues. Approximately 8.0776 Decillion C and above.

This trend can be extended to any arbitrarily high finite velocity and gives speed blocks that are easy to denote ("MFTL++" or "MFTL(2)" for instance)

Obviously most speed feats will easily be within the first 2 and most of the rest will be in the third.

If you wanted to go above finite speed, you could have infinite speed. You would actually NOT get infinite speed by crossing a finite space in 0 time. That's a basic divide by zero error. 10/0 does not equal infinity. You could get infinite speed however either by the verse explicitly calling it infinite speed or by crossing an infinite space in finite time.

Time Travel via speed is only as good a speed feat as the verse itself says. If you try to apply a velocity formula to traveling backwards in time you'd get a negative speed because it would be a positive numerator (positive change in space) over a negative denominator (negative change in time...going back in time) which would make the fraction negative. Or you're not moving in space at all at which point the time travel speed is exactly 0 since the numerator is 0. The argument some people try to make is that time travel means you can change the denominator at will making it take as long or as short as you want it too, and it's true but what you're talking about then is essentially a form of teleportation. Assuming you have infinitely fine control of the denominator this basically gives you the ability to go to any point in an arbitrary amount of time however this doesn't necessarily buffer your reaction speed at all, like teleportation, since reaction speed though it's often explained as a speed, it's actually not. Reaction "speed" is really reaction time since there is no spatial component, merely a temporal component of how fast you can react.

Anyway this was merely a suggestion on how to make very high speeds more immediately legible and understandable.