I think the problem as stated is insufficiently general. After all, why doesn't it apply with equal force to "I need eight maids a-milking?" Does that mean some specific eight maids, or any eight maids? In other contexts we talk about le bi vs. bi lo.
Any eight would be {mi nitcu lo'e nixli bimei}, "I need Mr Maid Eightsome" or we could also say {mi biroi nitcu lo'e nixli}, "I need Mr Maid eight times".
{mi nitcu bi lo nixli} means that there are eight and only eight
maids such that I need each of them.