Yeah... I know what you mean... finding truly flat ground is actually pretty hard... one spot I thought was flat.. ... I go one way and my time is always 1 second slower than the other way... so it is obviously not quite flat.
If it helps... WalMart and places like that have cheap stopwatches for $5 or $6... they function as a clock also.
Thats what I use.
... I just wanted some feedback on other faster peds.
(like caseys II !)