Before you retract your question, i'll answer the one that you didn't want to ask anyway ...
... if you have a manual slider you really never will forget to set it. And it is a good, viable option.
You get so used to watching out your rear window when you are driving around, watching to see how close th 5'r comes to the rear pillars, that it becomes second nature to know in advance just which turns will benefit from setting the slider back.
They are a good option. Certainly not as handy as an automatic, but significantly cheaper. That option made good sense to me.