This statement doesn’t compute in my head… you don’t have a ton of time available, but you’re willing to scrub everything by hand if need be?
Regardless, based on what you have said in this thread, I would say tuck your tail and pass on this job… stick to vinyl and make some easy money. You don’t need to buy “commercial SH” from a dealer… you mention Walmart, if you have a Menards nearby go grab a couple gallons of Pool Shock or go to a pool store and buy liquid chlorine, it’s 12.5% and sold by the gallon. Read a ton on this site… soak it all in. You may not think it is, but everything you have said has been covered before.
Just a small sample of what a couple minutes of searching this forum brings up, these answer most of your questions and at the bottom of each thread are related ones as well to expand on.
Chem test kit
Wood Ceiling
Composite Decks
Brick
Travertine pavers? Thats what the photo looks like, but I’m not sure
Nice Wood Front Door Damage
Deck Cleaning, but Really Any Wood
Removing Fallout
If you can’t kill organic material with your mix, then your math is wrong
