Helen,

One comment, your filter can't be too big. you will enjoy increased efficiency and water filtration with a big filter.

Does it sound like I've got a reasonable handle on my pool and current test results?

How low should I allow the PH to drop before adding borax?

If I keep a closer eye on the chloine level, can I leave the solar cover on for more than a couple of days?

How often should I remove the solar cover to let the pool "breath"?
Reasonable handle?...Absolutely

pH - Generally, 7.0 is a good bottom figure

Solar Cover on longer?...Probably, but just use common sense and check it often.

Letting the pool breath....I would remove it during bright sunshine and cover it at night for maximum heat retention.

Nice work getting your pool in shape. I'd probably back off on the pucks if your CYA tests got around 50.