2 months of work

Nice job, Resto.

I know what you're going thru, my ex-wife has MS. She just went to San Diego and had some kind of surgery to try and alleviate the symptoms somewhat. According to her beau, she's doing better. Not perfect by any means. MS sucks.

As a plumber for over 20 yrs, you've done an admirable job.

For the next project, skip the SOS. Too much crap in them. The sand paper, or better, an open mesh sand cloth available at any plumbing supply store, or maybe even a hardware store, is far superior. You are correct in the fact that skin oil will affect the cohesion of the solder. Clean it with the sand cloth, flux it immediately, and then solder. Once it's fluxed, you can let it sit for a while, it won't affect the outcome. Flux is an acid, more or less,it preps the surface.

Invest in a fitting brush, if you haven't already. It's a little wire brush, sized to clean the inside of the fittings. Makes life a lot easier.

MAPP gas is probably the best for the homeowner to use. I use an acetylene torch, but I'm a perfessional. lol.

To avoid burning the surrounding surfaces too much, try and pre-solder any parts that you can, and leave only minimal fittings to solder in place.

And yes, I would use copper in my house. I've installed all kinds of plastic/poly/pex in various establishments. I'm sure they'll last. But I prefer copper. Just like I'd install cast iron drain piping, instead of ABS or PVC. It's far quieter.

But what do I know. It's only the trade that I've been proficient in for a couple decades. And get paid quite well for.