Hi Sunbaby,
with your plaster being new, your pH is subject to rise fairly quicky. The TA helps control how quicly the pH rises, so, with a bit lower TA, like you have now at 60, that will help slow down the pH rise due to new plaster.
Also, running your waterfall makes the pH rise quick. So, another reason to keep your TA a little lower for now.
I would not recommend to adjust either the pH or the TA right now. The pH is going to go up by itself anyhow. Just keep an eye on the pH, and when it gets to 7.9, then lower it with muriatic acid to the recommended pH for plaster pool. AFter you get a feel for your pools appetite, then at that time, you can adjust the TA if you need to.
For Chlorine Level, the rule is the minimum FC is 7.5% of your CYA and a "target" of 11.5%. The target is just to give head room for it to drift down over the course of a day.
so with CYA of 70, your minimum is 5 and your target is 8.
And its OK if its a few ppm higher than recommended. Its just that that those few ppm arent normally needed and it wont harm your pool.
WIth CYA of 70, its safe to swim and safe for you pool if FC all the way up to 28.
Most folks test in the morning and add bleach to get to the "target". This gives them a few ppm of headroom for it to drift down to the minimum or just above it, at dark.
There are only two reasons why chlorine is used up.
First is that is gets burned off from UV from the sun (your CYA helps prevent that from happening so quick)
and Last, because it is oxidizing organic material in the water. Algae, leaves, bugs, dogs, full skimmers, people, ... all are orgaincs. The more people swim, the more chlorine you will use. The hotter the sun, the more chlorine you will use.
So, as you continue to use the pool and test, you'll get an idea of your pools appetite for chlorine. But ultimately - As long as you STAY ABOVE the recommended minimum FC, you are fine. As your PB said, the key is to be DILIGENT about it. If you get lazy, then thats when problems with algae occur. (BTW, great PB you have !)
Really though, your numbers are fine as they are. Your CSI is well within range too. So, until your FC gets down to the 5-6 range or your pH gets up to 7.9, there is no need to do anything except enjoy it.
I hope I haven't been too long winded, and that this helps,