Try putting in a touch of some blue into the highlights past blood red/orange. i.e. use slight amounts of space wolf grey with burning orange. I find that if I highlight with oranges through to yellow then what I obtain is too orange looking for classic red. Also look at a
red car in sunlight and you tell me if you see any straight yellow! Blue is required because highlighting by just adding white produces too pinky a red.
For the shadowing past some colour like red gore I usually use the complimentary colour i.e. red gore + dark angels green.
So my formula for a deep red looking red (from shadow to highlight) is something like:
red gore+dark angels green
red gore
blood red
burning orange
burning orange + small amout of spacewolf grey
This is just rough and each time I do red I mess around adding things like purples/blues to the shade and blues and yellows to the highlights until I get something that looks right. I get images from google of red objects and then sample the colours in photoshop to get a good idea of what they are.
Anyway that's how I do red.