New Brake Lines/MC - Questions

[b2948kevin]

Ok, I have my disc brakes in and am ready to route the brake lines and get the MC in. Below you see the MC/Proportioning Valve combo that I got off of a newer chevy.

Questions:
1. One line is bigger than the other. What gives? Do I need to keep the same size line throughout, or can I just use a bushing to reduce/increase the size however I want to?

2. Do the front brakes always feed off of the front port of the MC (AKA the back port of the proportioning valve I have here, as they swap places if you look closely)? Any reason to switch these?

3. Someone mentioned that there's a tool for unlocking proportioning valves for bleeding. Am I going to need this? Is there an easy workaround?

4. This MC/Prop Valve combo will work for my truck (along with Captains adapter, which I already have), right?