First: if Mark Scarborough, Randy Powell, Billy Biles or some other competent painter says different, then ignore this.

Second: candy colors are not one color -- they're an effect that you get with at least two coats of paint.

To make a candy color you paint a silver (or sometimes gold) base coat, then you paint a translucent coat over that.  So to get candy purple you'd paint the plane silver, then you'd paint purple over that.  Because the color coat is translucent, the paint job will be very sensitive to paint thickness.  This means that it needs to be sprayed, and it needs to be all one thickness or -- if you're really good -- of controlled thickness for shading.  If I tried to paint a plane candy color it'd be stripey and ugly.  I don't think an effective candy color could be done with a brush at all unless you (a) are monumentally good and (b) work the brush marks into the finish, i.e. make a candy woodgrain.

It'll be heavy.  This, plus the fact that it's hard to do it right, is why you see more candy colored cars than airplanes (and why you don't see a lot of candy colored cars).

Note that you can get some really cool, if subtle, effects by using candy colors over a solid base coat.  Candy red over black, for instance, gives you a black airplane with red highlights, instead of a black airplane with white highlights.  Candy over white will give you surfaces that are a deeper red when looked at from an angle than they are when looked at straight on.  And, I'm pretty sure (I hope Mark weighs in on this), candy over a solid color should be lighter.

well,,,,,,,,,,
deep breath,, I shall attempt to keep this to a truncated form,, I could write a LOT about this
first off,, if you are set ,, really set ,, on using candy,, then

my first suggestion would be to spray a base color of silver with some of the purple in it for the projected purple areas,, IOW mix some of the purple candy in with silver to obtain a purplish tinted silver,, then apply the purple candy over it. Mix the candy very thin,, if you are typically reducing the brodak dope 50 percent, then reduce it 100 percent,, when spraying the candy your gun MUST be patterend well,, IOW spraying a perfectly even ovoid shape with no light spots,, whimpy ends, or light in center,, I overlap about 70 percent with the goal to spray light coats but you MUST get enough material on for adhesion. Its a delicate balance with candy,, you need to have enough solvent to "melt" the new layer into the existing layers, but if you apply it to heavy you will get very nasty ugly streaks in the candy. Also alternate directions with each coat. so the first coat is sprayed for example,, wingtip to wingtip,, and the second goes front to back, the third diagonally from lower left to upper right, the fourth from upper left to lower right.. repeat as needed.
The number of coats of candy will affect the effect ( wow, never thought I would use both those words in the same sentance,, uh,, where was I),,
I would expect at least four to six coats will be needed especially over thinned. This should give you a nice rich depth...
from the last coat of tinted silver to the last coat of candy ANY dust will show up as dark spots and be very obvious,, you cannot sand and preferably wont touch the surface during this process as fingerprints can and will show through the candy,,

the same premise holds true for the pink.

Now for the deepest most dramatic effect you would not tint the silver base,, just start building candy over it,, but its even more of a pain to get a good job.

the good thing youhave going for you is that your plane is small, with lots of curves and few flat surfaces,,, this helps hide any difflugalties in the candy..
as to UV,, not sure if you have an addative for dope, or two stage urethane clear. My reccomendation would be a couple coats of catalized auto clear because then the UV protection is a known quantity,,
if this is an addative for dope, I have not experience with it, would be suspicious of it yellowing the clear in a short time ( just a historical experience, no direct knowledge of failures in dope,, never used it)
aside from that,, getting a "space blanket" or some form of covering to protect it when not flying which will keep the sun off it would be VERY VERY advantagous if you get a finish result you are happy with,, if you are not happy with what you end up with, then set it in the sun as often as you can and it will fade away,, and along with it your frustration ,, ( thats a joke son,, humor,, )
Hope this helps,,
I will try to check back if you have more questions..

Re-read Mark's comments, and you'll understand that while "civilians" think candy color is cool because of how it looks, anyone who is or who thinks they are a real painter (I'm the latter) knows that candy is cool because when it turns out right it's a difficult job done well.

My general rule is, don't do a finish that will embarrass me. I'll take passable.

This is the opposite of the Randy Powell I know.  That Randy aims for spectacular.  He usually achieves spectacular, but sometimes gets the heartbreak of psoriasis.  I hope you aren't getting conventional in your old age.

The number of coats of candy will affect the effect ( wow, never thought I would use both those words in the same sentance,, uh,, where was I),,

Wow.  If I ever attempt a candy finish that comment will effect how I affect the effect.

Sorry -- I couldn't resist.  I'll go back to work now.

Just for info, those are gurls colors, not for AIRPLANES.

HEY Purple is an awesome color,,

Yea, I was talking about his transparent finishes. The trim is, of course, opaque.