For the engines, I usually go with either orange or light blue, as I find those are the best colors to create the illusion of glowing engines, and with these ships, light blue seemed the best fit.
Sylar-Class Corvettes (Diesho Yen'Ming'Tao-Class)
Eandrir-Class Battlecruisers (Diesho Bao'Gung'Tao-Class)
Valerian-Class Battleship (Diesho Go’Jing’Tao-Class):
Feonas-Class Battleship (Diesho Yao’Jing’Tao-Class)