I can see you won't listen to reason, however I admire your enthusiasm
Plan the best you can, yes compression will be how you connect everything and you will want a drain valve at the lowest point possible.
It is inevitable if you try to buy exact you will need something and have to wait, be patient, take your time
Don't start stressing out if things go exactly the way you planned,
Most of all just have fun with it , did a copper tube build a few years back and it was a blast.
You can have a lot of fun if you don't get frustrated, keep it fun and don't set unreasonable deadlines
best of luck