We typically recommend 40-50 for CYA levels but usually there is a requirement for most SWCG that is stated in the manual. I'm not sure about the Intex SWCG though.

If your pH is that high, you do need to use some acid to lower it. Muriatic or dry acid will both achieve the same purpose. But, I have to tell you that test strips are notoriously inaccurate. If at all possible until you get your kit, can you take a water sample to a reputable pool store and ask them to test it for you?

I'll let someone else advise you in regard to the copper in your system. I really have no knowledge about those Intex SWCG setups.