Denny,

I have used a drop of Kodak Photo Flo in the past and it worked
well. What I do now is to

1) Use tap water. The water at my house is -very- hard.

2) Use small 1" squares of paper napkin (hard surface, no
fuzz on edge) to wick as much water off the model as
possible - by holding them in a pair of tweezers and
touching just the corner of the square in the edge
of the water (well away from the decal).

3) During this phase - perhaps two to 4 different wettings
(floating more tap water over the decal) - I will use
a long pin with a ball shaped end on it to prick areas
that are 'bubbled up off the model'.
4) After I have the decal 'setttled down' then I use
... sorry, but it is what I do ... Testor's Solvaset
for the final setting. I do -not- use a pin on a wet
decal that has Solvaset on it - too easy to drag the
pin sideways and destroy a part of the decal.

5) After the decal is fully set and has fully dried one
time after the Solvaset ... I inspect carefully for
"white lines around the outside of the decal" ... if
there are any I wash, usually only one time, with
distilled water.
- Jim