Unlokcit-
Couple things.
Cloning gels and powders do form a physical barrier.
The plant's stem heals itself.
And by watering the mother well before taking cuttings, you are basically saturating her.
Other than that, dip the cutting in your hormone IMMEDIATELY after making the final cut, and you should have no problems.

Another thing to add! I have recently fallen in love with dip-n-grow. It's got 2 different hormones, plus a fungicide, and costs like NOTHING compared to clonex, which has no fungicide, is expensive, and as far as I can tell goes bad in less than a year... and OMG is it easy to contaminate your gel...

Another GREAT trick for sanitizing your prop dome:
Scrubbing Bubbles! Yeah, the foaming bathroom cleaner! You can see if you have missed a spot because of the white foam. Spray on, leave for 5 minutes, rinse off.

With rapidrooters, if your clones have thin stems, make a slit with the blade of an exacto knife to stick it in so there is good contact between the cutting and the moist medium.

Hope these little hints help... I have been killing my own clones for years so y'all don't have to!