Parkman
Depending on how you want your flames to look, you have a couple options with color use. You can go over a red with a darker red (adding a couple drops of cobalt blue kandy, maybe one drop of green Koncentrates to some kandy apple red in House Of Kolor SG-100) That will make the flames a darker red & keep the flames translucent in color. Another, maybe easier & cheaper option is to get a shade of dry pearl (maybe silver, or gold) and mix it with SG-100 and lightly spray your flames. The flames will contrast the base color, but with Pearl the will pop out and recede as the light hits it.
Other options are to make solid color flames that totally pop up and contrast the base, but compliment your kandy red color. Like silver flames on a kandy red for example. Just some examples of what you can do.
In step 4 you can use a red scotchbrite pad instead of sandpaper and get the surface scuffed up, w/o the risk of chewing through the clear. One bit of WARNING though, be extra careful and easy around any edges. You can sand through layers easier in those areas.
On step 6 with the mid coat clear (SG-100?), it is advisable to wait an hour after spraying before applying any kind of tape.
With your project it looks like you will only need small quantities of material to complete your job, so I wanted to mention
www.coastairbrush.com. I don't make a dime off of this, but they will sell you kandy koncentrates, dry pearls etc. in very small, to large quantities. If you went with pearls you may only need an ounce to complete your ghost flames.
good luck & have fun!