major Wilwood brake bleeding issues! 10+hrs in

[gnx7]

I have the following setup on my '69 Chevelle and am having a nightmare bleeding it.
Wilwood master with brake booster
14.25" front Wilwood 6 piston calipers
11.88" rear Wilwood 4 piston calipers
custom lines with prop valve

It simply seems like the master isn't moving much volume at all. This is a new brake system 100% from end to end with no fluid in it. We went to all corners (furthest first) and it took a very long time to get the air out in the system (still some air in there) about 6 months ago and easily 2 quarts of fluid put into it (3-4hrs time). I finally took off the Wilwood master cylinder and bench bled it where I could see plenty of fluid moving as I would make the stroke happen. Then put it back on the car and as I am a small biz owner I finally had time to work on it again now that summer is over. We did the same process over again and same crappy results. We even used a power bleeder the 1st time... (not the 2nd time though).

I'm guessing the rod inside the master is too short and isn't pushing the piston far enough? The shop next door to mine suggests that it is fine... and I should take some washers and space the master further forward away from the firewall as the back port may not be fully closed which is making this happen. They said it has happened to them a few times and once you are able to bleed the system you can remove the washers and all is good.

Does this seem logical? Or should I put a longer rod inside the master itself.