Just a quick correction it's series that raises voltage, parallel raises amperage. It's not that difficult to do this safely solar equipment is all made with safety in mind. For example it's pretty rare that you should be working with raw wire especially any that is any type of live. The only time you will potentially be exposed to Raw wire is when you're initially making mc4 connectors but they should not be plugged into anything while you're doing that the panels will already come with their own mc4 connectors obviously you should fully make both ends of the cable before plugging them into anything.

Copper versus clad aluminum should not matter as long as you are using the correct size wire for the amount of amperage you expect to see, that's the same issue you could run into with house wiring so it's really no different than that the AWG sizes are standard and all come with load ratings. Regardless of the type of material it's made of if your wire is getting any type of hot it's a sign that you need a lower gauge wire it shouldn't be getting notably warm under load much less hot

There is indeed some math to be done to make sure that whatever type of inverter you use will work with the solar panels and arrangements you plan on using. It's some pretty basic math not particularly difficult, i do expect anyone doing DIY to do the bare minimum of reading the instructions. Don't get me wrong there are some stupid people out there, like the people that leave one star comments on an Amazon product saying that the bottle is smaller than they thought even though the listing says the size of the bottle in the title and the description. However I am not going to base my general recommendations on that level of intelligence.

If you do some very basic reading, look over the description of the products which will also tell you what type of voltage they can take how many amps and usually any other considerations it's pretty easy to put these things together correctly. And it's fairly easy to put them together without ever actually having to interact with live voltage other than the final connection which if you really wanted to be ultra safe about you could simply do at night when there wouldn't be any :) there's countless information available that you can research beforehand if you're ever nervous. Tons of great videos out there tons of great content on stuff like solarDIY forums etc