Yep, that's true. I just thought I needed to mention that, since you wanted to make other players aware, it was worth mentioning something like "Do not overwrite slots 49 and 50 with your manual saves. Those are for quicksaves and autosaves"
You can practice on Jane in the evening when she's watching TV. And after dinner with Jessica you can practice on her clients (although at that point your massage skill would be practically maxed). So mostly Jane, you can practice 2 times per evening with her at 22:00 and 01:00.
And concerning variables and save editors there was this advice recently:
https://f95zone.to/threads/college-life-v0-3-1-mikemasters.2625/post-2935599