How to properly plumb a tank?

[-=James=-]

What is the correct/best way to plumb a tank? First, let me say that I have no experience in plumbing. I even underestimated the cost of all the materials.
Basically, I need to know how to connect everything after the bulkhead.

My bulkhead is a slip/thread. Thread side in the tank, slip side going to sump. Heres what I currently have planned:

I will be using union valves (after I found out they exist) but use this pic as a guide:
Bulkhead -> union valve -> sump


I would have to use those 2 white connectors (at the end of the union and ball valve) on the union valve since its double threaded.
Then I connect the slip side of those connectors to PVC pipe, which connects to the bulkhead.

BUT, an important factor is for me to be able to disconnect the bulkhead from whatever attached to it just in case I need to remove it, so glueing the PVC to the bulkhead might not be a good idea.
Maybe I can buy thread/thread bulkheads?

How does everyone plumb their tank? Should I not bother trying to be able to disconnect everything? Thoughts and ideas please!

Thanks in advance