Brake line / prop valve questions

[Chris4x4Gill2]

I am trying to finish up a rear disc conversion on my 72. I am using the wilwood adjustable proportioning valve with 3/8-24 fittings. I have redone my flares multiple times and I cant get the lines on the bottom to seal, they keep leaking. The lines from the master cylinder seem to be good. I'm about ready to throw in the towel and try to find some pre-made/pre-bent lines with the proper fittings - do they exist for my application?

Can anyone tell me the fitting size for the factory proportioning valve? I no longer have the original that came off of the truck. If they happen to be the same size fitting, any reason I cant use one of these pre-bent master cylinder kits?

Wilwood Prop Valve:
http://www.summitracing.com/parts/wil-260-11179

Lines:
http://www.lmctruck.com/icatalog/cb/full.aspx?Page=166