Cobra with C&L meter

I have a buddy that has a 94 Cobra, he ordered a C&L meter for the 24# injectors that his car came with. They sent him one that had 19# on the box, he called them and they said it would work with 24s. His car is not running correcly(he changed a few other things).
Has anyone else that has a Cobra gotten a C&L? Which tube do you use?

Thanks for any info!

Right, but I wonder if the C&L uses the 19# tube with his 24#ers since his electronics(which he took off his stock meter) are already calibrated for 24s.