LFNC-B is a non-metallic conduit, so why do you need to keep it 1/4" off the beam? I always thought "sealtite" was LFMC, and since that has metal would have to be off the surface. LFNC is cheaper, non metallic, and easier to work with.
Will you have any issues protecting the conduit from physical damage? You could also use UF cable. It should have the same physical damage constraints and plastic conduit and may be easier to protect because its much flatter.
