First thank you, and glad you enjoyed it!
Since you have a Jap Tissue covered wing, with dope (even though it is sealed minimal), you would lay the cut out numbers and other graphics on the wing, and while holding them in position lightly with say a dull wooden skewer, then brush on some more Dope. They should lay right down and stick really well, looking painted on. As far as repositioning, that is possible with say tweezers, but not too much because once wet, the tissure is all but bonded. Jap tissue shouldn't bleed either with proper application of dope, but please always do a small test piece to practice and verify your products.
There is a free flight forum where the guys do exactly what you are describing all the time and they probably have other tips if you just ask!
Good luck and that to would be some good photos to share here to show everyone else a different twist on using tissue for decals!