Justin Szeliga

Lift with your legs, not with your eggs.  Bend you knees, scoop up a little less than you can comfortably lift, & treat it as a mindfulness exercise.  That always seems to get my snow cleared.

Just say no to WD-40 unless it's sticking.  WD-40 is designed to free up stuck parts & displace water allowing lube to get to the surfaces in contact.  There's only a  bit of mineral oil in it.  The oil mentioned in the first reply was likely 3in1 oil or something like it.   Very good choice.  Oil, use, oil again after using for a few times to clear out the corrosion.  Spray lithium grease is good but will be hard to get to coat the whole shaft.  
That said depending on the wheelbarrow there may be a grease (zerk) fitting which you can pump grease into, which is the best way to lubricate the shaft & bearing, & the absolute most satisfying. Watching the grease ooze out of the wheel hub & the squeek going away is sooooo, nice.  

Ellendra Nauriel wrote:\ you could mix it with salt and sprinkle it on popcorn.

If you used salted butter you don't need to add salt.  At all!  The salt concentrates in the settled stuff.  

If you stress tempered glass just right you will crack it, & that crack will propagate with remarkable speed all across the pane .  Interesting thing to behold.  Try sharpening on someone else's car window maybe.

One thing for tile info-  https://www.johnbridge.com/vbulletin/  .  Great bulletin board for tile installation info.

AH.  The dust removal.  Fans in the windows blowing out, windows on the OTHER side of the house open so you don't loop the dust through the house.  I trashpick box fans for just that purpose.  
I've found it more effective to create controlled directional flow into & out of the room than trying to seal it off.
Plus it gets the dust out of the air in the room making clean up & visibility easier.

Dirty.
Dusty.
Filthy.
Backbreaking.
Seemingly neverending.
Questioning one's intelligence & abilities & reason for existence.  
All experiences I've had doing smaller areas of leveling like that.  It's a brutal job, it's doable, if you don't have patience it's a bad place to try to acquire it.  But it can be done.  Floor leveler is really expensive due to the thickness' it needs to span & be able to support the floor above it.

One other thing is that the more hydraulic, the harder that is generally, the harder your materials being cemented together need to be.  Using modern bag mortar with old soft brick or even a soft enough stone will, if exposed to the elements, cause a deterioration  of the softer stone or brick. The softer mortar made from an air cure lime will take the brunt of any expansion & contraction in the wall, while a harder hydraulic mortar will attack the material it's holding in place.

Could you use PVC pipe, either as posts to support a beam acroos the top of the HK, or just make a pvc hoop greenhouse & HK the northside of it? Bury 1/3 of the hoop in the HK?