Yes, Waxoyl is not the best but better than nothing.
If you are trying to follow originality, it is very difficult to get the detail right.
On my GT6 restoration, as much as I like originality, I'm thinking of the chassis in black just because it's neater than relying on overspray for a finish so it will be body color body/underneath, black chassis.
I'm thinking of a stone chip with top coat in body colour for floor pans and underneath wheelarches but just body colour for the rest of the front bulkhead.