Painting/Bits & Pieces

1968FormulaS340 said
"be careful when spraying metallic." is an understatement.

Don't panel paint a metallic at all. Gun speed and gun distance will change how the metallic lays and how the color is perceived by the eye.

If you panel paint a metallic everything will be slightly a different color.

You can see this all the time at car shows. One way people hide it is by showing their car with hood, doors and trunk open.

agreed, even pros have issues with metallics. (I am doing mine, myself- not a pro- but I think I can do it....)

back to the op, it makes sense to pain the insides, jambs, etc in pieces. this way you can assemble the car and get all the (visually) contiguous parts shot together. This presents its own challenges to avoid hard lines/edges inside the door jambs, cowl etc.

some of this can be avoided by applying the paint at an angle that is not conducive to load up the jamb and/or shooting near the jamb area "hot" (over reduced to it goes on thinner and melts in a little.

This does require some advanced masking technique as well.
this can help: