How to bleed coolant?

Ok, this is the cheapest micrometer ever, they sell them at harbor freight for less then $10, but it can measure inside and outside diameter. Its not designed for mechanical measurements that need to be super precise, but it will work for your needs, I use this thing all the time when doing 3D printing. The smaller side facing kind of up on the left side is for taking inside measurements, you can use the jaw side for measuring outside diameter if needed.

Yeah, the rubber hose should be able to stretch enough to fit over the plastic fitting, and then a hose clamp around it. I check out your videos real quick

Yeah I saw the TSB for the hose installation. It seemed like the basic idea was to have a higher section of hose where any air in the system would be able to rise to and then exit into the expansion tank. Thats why they put bleeder screws at a high point in the cooling system, the issue with the cooling system right now (stock) is that air pockets are getting trapped in a location where there is no higher location for the air to go, technically the vacuum down bleeder method is supposed to take care of that, the downfall I see to the method is some coolant leaks happen under positive pressure and can be missed when its under a vacuum due to the negative pressure, or lack of pressure.

In the 2nd video that whitish section that the hose came off of looks to be about 5/8in or so, you could just measure that with a tape measure, then you'll know the outside diameter of that section you need to fit a hose over and the size T fitting you need. It looks like with that bleeder being there as well, that will now be the highest point for air to escape, even from the expansion tank which will help.
Next you will need to see how big the inside diameter of the hose go to the expansion tank is.

Yup the hose coming from the heater core hard line was probably a quick disconnect, so just put a regular hose clamp over that once you get the T ready and a short piece of hose to go in between the T and heater core section, it looks like 5/8" to me but measure it with a tape measure to be sure, just remember to run the hose under the air intake boot so any trapped air will travel to the bleeder screw