I take a unit of 9 horsemen with light armour + champ to bunker my hellsteed vamp lord, and they basically only exist against enemies with cannons otherwise I use them to hunt warmachines and clear chaff.
Yeah the unit is tiny, but since I'm not really concerned about breaking steadfast anyways I just run them 2-wide. That way only the VL and the champion can be attacked, and unless they get flanked there's only so many wounds that can actually be put on the unit.
It's not as effective as a BK bus, but it's also way cheaper, and more maneuverable/durable than a VL on foot. And if the opponent doesn't have cannons then I just run him in with whatever unit I feel like anyways.
As for other points, DO NOT use the casket to chip away at mainstay combat blocks. Do it when you don't have another good option, but with LD10 rerollable you're very unlikely to do much of anything. Instead use Light of Death to target warmachines, chaff, and flanking forces...i.e. things that aren't benefiting from LD upgrades.