Yeah it's a tongue in cheek statement lol

Half of the world's population is below average intelligence

Five foot eleven and a half?

Risk of misinterpreting that as 50 inches if someone's not able to see the decimal clearly. 5 feet = 60 inches. 4ft 2 = 50 inches. Risk of someone setting it up far too high or low

It should go 4 ft 11 in, 5 ft, 5 ft 1 in. But it says 4 ft 12 in instead of 5 ft. 12 inches=I foot.

Looks very Monty Python

Sew it with a curved needle and matching thread. First knot can be hidden by going in the hole and up by the edge, final knot you bury by going in the end of the hole, come up about a half inch away (any direction) and cut the thread flush with the fabric, end of the thread will just disappear.

Glue will feel crusty and be much more obvious

Is one of them pee? Hard to tell with Mtn Dew

You could probably get timber cut to length at any home improvement store, just measure the lengths you would need. Move the existing hardware over to the wood, using the mdf as a template. Extra wood blocks under the rails is a good idea, you could also get some prefab furniture legs at the home improvement store to go between the rail and floor to help carry the weight too