Back in 2010 when I built this bike I kept a running thread of the build over on ADV.  But then all of my Photobucket links got broken so that thread became pretty worthless.  So a few years ago I took the pictures and converted that thread into a web page. 

It went from this:


To this:



And here's how:
http://www.kbikeparts.com/classickbikes.com/ckb/1.my.k.bikes/10_K75F/k75f.3.build.htm

Okay... now I understand your comment about not liking Dowty washers for the hydraulics. I am not in the slightest bit surprised that the rubber seal tore out when you torqued them up because of the shape of them. These are Dowty washers:-

https://www.ebay.co.uk/itm/Dowty-Seals-O-Rings-Bonded-Seals-Self-Centering-Hydraulic-Pneumatic-washer/132776054122?hash=item1eea11cd6amDsGCqRbfis89vgTGxmV10Q

I picked this picture deliberately because you can see the double-lipped circular seal which yours did not have. You can also see that the circular seal would not be caught up when torquing up. Another good thing about Dowty washers is that if you've bled the system and then find that the banjos are just fouling something (as I did today - one banjo on the master cylinder was rubbing against the back of the instrument housing) you can slacken them off slightly, move the banjo and re-tighten without getting air in the system.

The downside is that it's possible to bleed the system and successfully bring it up to pressure when you've only wound the banjo up finger-tight . No, it didn't leak and yes, it retained the pressure for three days before I found it by accidently against knocking it.