Are you suggesting alligator clips just to keep the cost lower?
Since the TIU has banana jacks built in, and this project is intended to just test at the TIU itself, I'd be inclined to put banana plugs on the end intended to mate to the TIU posts. Just the plugs seem to be about a buck a piece. Using a pre made test lead would raise the cost of the project significantly though, I guess (well, maybe $5 per lead - not expensive, but double the $10 we started with )
-Dave