Watching various videos and instructions from others, I found that there’s no need to remove the screen if your goal is to only swap out the battery.

It’s meant to make it easier to clean off the old glue and install some double-sided adhesive tape but it was far more simpler to loop the tape around the screen with a pair of tweezers than to try to wrangle with the metal bracket securing the display and digitiser cable connectors.

T-7000 glue can presumably be used in lieu of double-sided adhesive tape but it’s definitely more messier.

Anyway, I was initially quite annoyed about my battery expanding and popping the screen off but very quickly got over it when I realised it was a simple $20 DIY fix. Guess I got lucky this time..

Use the teardown guide for your iMac to familiarise yourself with the layout of everything before you dive in. I was able to get an idea of how much clearance there was once the display is unfixed from the frame, where the optical drive was relative to the base etc

No need to remove the thermal sensor connector from the motherboard - refer to Step 17 to remove the sensor from the optical drive instead

@AliMir - yes, you can reattach the thermal sensor to the new SSD

Just completed the replacement of the optical drive with an SSD using an OWC Data Doubler kit. Attempted to remove the optical drive without disconnecting any cables but found it a bit fiddly to orient the screen for good access. I bit the bullet and disconnected them and found the process less daunting than I imagined. Reconnecting them was similarly straightforward if you're careful.

Tip: you can skip the step for removing the optical drive thermal sensor connector from the motherboard. Still need to remove the sensor from the optical drive but you can leave that hanging and reattach it to the SSD later.

+1 for the straw tip. Worked a treat!