That could actually explain why the Valkyrie and Perseus have "wings".
Wings and long noses may be used to position manoeuvring thrusters further away from the primary mass centre ensuring better manoeuvrability in combat.
possibly coated with rubbery ablative substance
that will melt instantly after the first hit?
Fighter hulls must be constructed using multilayer composite armour technology - just like modern tanks.
Outer layer - ablative heat and particle dissipation (possibly carbon based and nanostrengthened) material that will diminish depending on damage rate but insure other layers are intact. Outer layer is also very easy and quick to fix even on the battlefield (to apply small portions of fresh material in a gel form over the diminished one and wait till it hardens. The gel has its own "memory" and will take a different form depending on the part of the hull it was placed on, so you won't have to polish it or anything like that and any extra portions of the gel applied will simply fall of the hull by themselves or after the wash.) or by replacing damaged and diminished sectors of the armour with new ones in the hangar.
Medium layer - thick and tough layer of conventional plating made of, let's say, wolfram-titanium-carbon nanotube composite. Insures protection in case the outer plating has been breached. It is relatively not heavy if to say about the mass, but not as light as the outer layer. Very tough and resilient but all heavy damage to it is permanent, so damaged sectors have to be replaced.
Inner layer - smart fibres coating that protects from radiation and heat in case of massive hull damage it also has self sealing abilities insuring integrity and protection of the crew and equipment.