I think there's a few important questions that need to be asked when dealing with Time, they are How long is a Length? and How long is a race?
I personally use Time as the most important Variable.
To me, its not the distance of Todays race but the distance raced by each runner Life To Date(LTD).I use all a horses LTD formlines.
If you plot Track records by weight carried over each distance at the major tracks you can develop an accelrartion/deceleration matrix based on those Fixed Points, you'll then find the Slope/Intercept Standard, this will provide the first crosshair in pinpointing the Speed ability of each horse
The answer to the first question, in gryhound racing they assign .066 as the time for a length, but this is inacurate, think of a distance race the speed of the winner and the speed of a short sprint race winner as they cross the line, the time it takes to travel a length is different..
Cheers