Air Line Plumbing

[ca180]

So, I'm trying to figure out how to run my air lines. I've seen lots of diagrams that are pretty useful, but have some questions.

1) Is it better to keep the valves close to the tank and run the lines to the corners, or put the valves close to the corners?

2) If I were going to put them close to the corners, should I hard line everything up to the valves and run only a short section of flex?

3) If I plumb the valves close to the tank, is it ok to run flex lines that long?

I'm wanting to stay as safe as possible, and not have to redo this all later. I have 8 1/2" valves, one 7 gallon tank, and a thomas 327 compressor. Hopefully I can do something....

Thanks in advance