If you're married to sisto, -ere the form would be sistite, but I wouldn't go with that verb. It seems to mean check in the sense of stopping something's advance. I think you want a word that means examine. Perhaps investigo, -are. The proper form would be investigate. The experior is OK for word choice but you want to say experiri

Thus:

INVESTIGATE ET EXPERIRI

or, if you want to sound a little sexier:

INVESTIGATE EXPERIRIQUE

If you don't like what looks like an English word stuck in there you could use inquiro, -ere and say

INQUIRETE EXPERIRIQUE