Bore rust

As said before, you need a rust remover not another oil. Past time for that. You can make something to bolt to the deck surface, add plastic sheet, rubber etc... to fluid proof the surfaces. Turn block over, upside down ( assuming it is in an engine stand) and fill the cylinders, one side at a time with a product like Evaporust and let it soak for a few days. It will not remove any metal or affect the honing. Be creative.