Even "Reaper Miniatures high density" paint would require 3-4 coats.
Id recommend a trick from traditional painting. If you want light colors to be bright and "shine" then apply your color in a transparent wash over pure white base. The white will "shine" though a color wash.
The transparency is the key. Its like a watercolor effect, the transparent color wash will always be brighter than same exact color applied opaquely from the can.
I always try to paint all sections and details in white first. Then wash in my yellows and oranges on top.
If you want the orange to be super intense you can:
1 - I was using Aribrush type tool and an orange Oil-Based marker. worked out well.
scroll down to example, reaver bikes,
https://www.dakkadakka.com/dakkaforum/posts/list/760381.page
2 - Mask off areas and use bright orange model spray can. If that is possible to do.
3 - Paint the oranges using oil paints instead of acrylic. However that might require some practice.