Sealing decals on Alclad finishes

Any sealer you apply will change the tone of alclad.  You can brush on some clear coat on the decal only.  A laquer flat clear will leave no brush marks.

To clean dust from ceiling or shelf bound models, I simply hold them under the shower and let them drip dry after.  The delicate parts never get broken that way.

Future will leave a glossy coat if that's what you're looking for.

I usually seal in my decals with flat clearcoat, not Future. Besides, I used to hang them on the ceiling but never again. It became such a hassle dusting them off plus you risk breaking off delicate pieces, like propellers, machine gun barrels, antennas, etc... From now on, I'll display my kits in glass display case or a used curio of sort.