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..