For the best coverage and optimal shine... nothing but auto body paints
for vinyl dashes that do and will flex, SEM paints (auto body paints can have a flex agent added to do the same with optimal shine)
for a decent shine, do it yourself, and a fair price, pick any of the duplicolor hues that you like....
you don't need hi-temp clear... in fact it will dull your finish more than a normal clear will because of the ceramic content.... hi-temp paint is for 500+ temps... the most your car will ever see on a hot summer texas day with the windows rolled up in the sun would be 250* tops and that's quite high... getting above 200* if far fetched....
mind you before painting, prepping is very important... if you want it shiny you'll need to sand it first as smooth as you can to remove all textures and imperfections, then prime it first, and sand the primer... this will give you the smoothest possible finish.... for deep textures (like the a-pillar), a high build primer should be used, it will save you hours in sanding....
Finally a shiny dash will glare off your windshield on a sunny day.... just put a towel over it and you are fine