Also remember to either swap around the sump washer on the plug, or replace it entirely! This is important to avoid leaks.

Tighten to spec, if a torque wrench is available.

I would start the whole procedure here, and continue to removing the oil fill cap. The oil will empty much smoother, thus avoiding to spill oil everywhere.

External thermal sensor for an ssd upgrade is not needed for this model. Only for the mid 2012 models and earlier, so you'll be fine

I've just added some steps, for closing the iMac backup. Please revise them if needed.

But you guys need to take notice, of users cracking their display glass and getting vertical or horizontal lines, when following your guides, as the guides are VERY far from Apple's iMac Service Guides!

Also, from step 18 through 22, the iMac needs to be standing upright, NOT lying down, as you can easily damage the glass when lifting it like that.

I'd like to note, that it is in no way necessary to save the wedge for when the screen is removed. In fact, the wedge is used when removing the LCD, because the rear housing may tilt when removing it, and the wedge counters this.

So, for your own sake, DO NOT lay down the iMac, but in stead, leave it standing upright, with the wedge in place, when removing the display, and let it stay there until you're done with servicing your iMac.

By the way, a minor detail you guys left out;

The tape strips for the 2012 and 2013, are not the same as 2014 Retina model.

The WiFi antenna's are located differently on the right. It's slightly elevated on the Retina, compared to the 2012 and 2013 models.

I'm surprised to see, that you install the tape strips on the unit lying down.

It's a lot easier to attach them with the unit standing upright.

Also, attach ALL the strips to the rear housing, NOT to the LCD.

Attach the tape strips to the housing, mount the display, use som painters (/masking) tape, when you have aligned the display to the edges of the housing, attach the tape to the bottom of the glass and rear housing, making sure the display won't slip out of alignment.

Then, tilt the display towards you and support it with either a hand or your chest, while you remove the tapes protective layer and tilt the display back.

That way, it's still well aligned and it won't shift.

Same goes when removing the display in the first place.

Don't lay it down on the table - use a wedge, to make sure that the housing doesn't tilt while removing the display, and let the wedge stay there unit finished. The display is a lot easier to handle when upright, and you won't put too much pressure on the edges of the glass.