We have an old Lister Cream Separator as well. It was interesting the first few times we used it as we thought it was broken as the milk didn't separate and then DH found this website with information from a book or manual written in the thirties and we did it!!
Over time we've worked out what works best etc and bit by bit have worked out how it all works and fits together.
The cream screw is important as well as it gives you more or less cream by how far it's screwed in.
When you get it if you want to talk over the phone just PM me and we can talk.
You'll LOVE the results from separating with it, way different to skimming.
I had a jersey years back, I raised her on a bucket, she was absolutely the most beautiful animal. These days we have Dexter cattle which we've yet to milk, get all our milk from a dairy at the moment and have for a few years. The Dexters apparently have almost the same butterfat content of the jersey but are a beef breed as well, and are a bit smaller than the jersey... what breed do you put over your girl?
I've used the vacola jars, recycled jars and mason jars and believe the mason system is better than the vacola, but who cares if the results in the jars are good.
I did mandarins approx three years back and laboriously pitted and got all the pith off them to bottle and they turned out bitter as well. Then I read in my very old Vacola book (1930's vintage I think) that I should have done them in a heavier sugar syrup rather than a light water one... I think we get so bogged down today with low sugar/low fat that we forget that some things need it and it's not always bad for us... more to the point it's how much of anything we have rather than having it at all.
Look forward to hearing about your separator when it arrives.