There are several questions about hibernating (suspending to disk) but most are concerned with battery life and so many answers basically say just use sleep (suspend to RAM) because the battery will last better than you think. Other answers are simply out of date.

I don't want to use hibernate because of battery concerns. I want it because the SSD is dead and I use an external USB 3 hard drive as my boot drive.

It's almost as fast and I'm happy with it. But if the cable moves too much while the MacBook is in my backpack the OS will crash and anything that was in RAM is lost.

I've read that MacOS has several heuristics about when to suspend to disk (hibernate) rather than ram (sleep) and that one of those is whether any USB devices are plugged in, which for me is always yet.

I have sudo pmset -a hibernatemode 25 but when I put the Mac to sleep now it starts right up when pressing a key or plugging in the AC, which tells me it's not suspending.

Is there a way to really suspend my MacBook to disk, then safely remove the HD, transport everything, plug the drive back in, wake up the Mac, all without losing what I was working on at the time?

Mid-2013 11" Air / Sierra 10.12.6