That's a tough one. First thing I would say is don't plan on a run time a sales man gives you. As for the old machines, we have an old Citizen L16 that never gets used cause when we look at a job to put in it we always come to the same conclusion - it will run faster and better in one of our newer L20's. Instead of planning on buying this machine for this one large job look at other jobs in your shop that could be manufactured in this machine at less cost to you. We have taken many jobs from our lathe and mill departments that took multiple operations to complete and now it's done in one op, which means less set-ups and less handling of the part. And for ghosting it comes down to the job, we have jobs that run overnight and other jobs we can only get a handful of parts. My question to you is, do you guys have any experience with Swiss screw machines? If not there is going to be a learning curve. So I say, A: go for the new machine and, B: get a machine that will run this large job but also help improve other jobs in the shop.