I hate decals, and they hate me. Paint stencils?

Try cuttin'  your stencils from frisket paper...  It's self-adhesive and works pretty well.. It's designed for artists for masking their areas of paintings, especially those guys that do military aviation art and airbrush paintings...  Another alternative to water-slide serial numbers and squadron codes is Archer Dry Transfers..  http://www.archertransfers.com/

Also, there are a number of dry transfer letter and number sets in the model railroad section of your LHS..

One thing I have done to make "stencils" is to print out the design/number on label stock.  I then press it onto a sheet of masking tape. I now cut out the number, through both label and masking tape. I remove the label, apply just the masking tape, and airbrush the number.

Do NOT use just the paper label material- paint will leak through if you get paint too heavy.

I see you've waited since late last month for any suggestions about decals. If you have in your decal stash some your not going to use I would suggest using them for practice on a model that has on value to you. But only after you do a google search on "appling model decals" and read over what others do.

I sort of sounds to me the problem your having is adhesion of the decals before you have them in the place where you want them. The thing I do is add 3 or 4 drops of (my estimate?) dishwashing liquid to the decal water, 1) place the model on its side using two stacks of old paperback books each topped by a pad of old socks (built a plywood cradle with felt pad in a 'V' notch to lay my 1/48th scale models on the side for decaling), 2) clip out some decals, using a 1" wide paint brush paint the spot for the decal with the water/soap solution, soak a decal in the water/soap solution, 3) holding the wet loosened decal supported by the paper with one hand take the 1" brush and redampen the spot if needed and slide off the decal using a wet index finger as close as you can get it to the spot it needs to be, use final positioning can be accomplished using a wet pencil eraser. Once the decal seems its going to stay put carefully use a paper towel to soak up the water without touching the decal (I'm fussy about lint so I use coffee filters). Now its time for decal setting agents. I can't quite see how to use a stencil without leaving a paint ridge between paint colors, whoever I certain there is plenty of modelers who can pull it off.

I found both USAAF and Luftwaffe fonts which were both free on the web and I have the free version of Photo Filtre to make standard decal sizes, plus the software will allow you to make letters/numbers that are one of a kind in width or height. The fly in the ointment is white decals of course. Guess thats the some total of my thoughts. Danny aka Hogzilla