Sr 71 blackbird kit ?

im working on a revell sr 71 blackbird kit(i recommend to anyone to buy , its only $20 and its 1 foot long!)and ive got to the stage of decals... if youve seen a picture of the blackbird you'll see on the back half of the body , on both sides of the plane two red stripes. Now these stripes are about 8 cm long and very thin , and im worried if i put it in water too long it'l be too week , or if i put it in the water the right time but apply it wrong it might break?is there any tips on how i can apply these tricky decals?also to cut out the decals should i use small sciccors or a hobby knife? and does the thin semi-transparent sheet that comes with the decals do anything? thanks