Ambulance orange 8" reflective stripe: 3M or GMI 8100EG

In my opinion and experience, you need the 3M 680 as it is designed to be conformable.

Per the JSI website, the 8100 series is "..designed for use mainly on commercial signs and various labels".

 

Use the 680cr. Put primer94 in the "groove."

 

3m 680 is the way to go, air egress is aggressive. you may want to pass on wet applied. and that countour may distort the color of the tape. if you have ever applied a reflective tape and pulled it to conform to a sharp curve or lets say rivet you can notice the reflective color turn dark. you actually pulling the refelective coat apart. just informing you, you sure dont want a color dispalcement on that line all the way around the van. your best bet would be applying the tape from top to bottom, maybe peel back and inch or two from the top and slowly conform to the curve as its fed from the bottom. 3m cr680 has a great conform-ability but you will need some practice. also dont apply in high temps make sure the vans surface is cool to the touch and dont use a sharp squeegee. good luck!

 

van ambulance

that groove huge pita... rear corner over tailight is a
night mare

 

I would backroll the vinyl lengthwise and apply top to bottom so you didn't stretch the groove, saving the corner over the tail light for last. (leave the backing on that part leaving a folded tail to pull from)
FYI - I never apply reflective wet... & I would remove the tail light lens, but I'm sure you already planned for that.

 

Here is a tip for that pain in the rear back corner...

First hand cut a couple of bits of 8" or whatever highth your main stripe is going to be out of app tape about a foot long. Stick those to the van on the rear and side ov the van to about 8 inches from the corner. Then cut a nice oversize hunk of app tape and apply it to the corner. Hand draw on the app tape with a pencil around the corner to the pices sized the same as the stripe you applied first. Carefully remove - scan/photograph your handiwork, then trace that in Illustrator and add it to the end of the main stripe shape. Now you have a nice funky upturned curve on the end of your stripe that will run around that corner easily.

I simplified this slightly on the tracing part but I hope you get the idea...