I get my Form from the GRV Website.
Formguides like from The Watchdog display the actual time ran by the animal.
I can't help you with sources elsewhere.

Dogs are about a metre long so a length would be a metre.
They usually run about about 15 metres per second towards the end of the race , so thats what I use , 15 lengths to a second.
But like I said , the work is already been done with the Victorian guides.

I posted an Excel Sheet that I ripped off from member Kennedy91210 that downloads FormLines from eForm at GRV.

If you interested it is an attachment somewhere in this Forum.