HI Darryl, sorry I was tired last night so my reply wasn't particularly helpful.
Anyway, after finished shopping today I decided to have a play, I didn't bother with constraints, the bottom (glass) figure uses a simple custom script, the top figure is a formula typed into 'set attributes' , I used, 3 seconds x 25 frames per second (AVI) = 75 frames, distance 125.25 divided by 75 = 1.67, so each frame the figure and move should increase by 1.67mm, the text is flexible with thickness, so should always show up. (I used RedSDK).
the GIF is actually longer as I didn't bother altering the above for a GIF save. the seconds, frames and distance required playing with so the final figure isn't something silly to 10 decimals.
Just my thoughts, and an example of an alternative way of doing it (there will be more ways
). the calculations / formula can be improved a lot, but as I say its just an example .