Don't know where to start really,
I need a Brake master cylinder, with my limited space constraints, I don't have room for a dual circuit master cylinder in the traditional position, No servo either.
My braking consists of Tokico 6 pot callipers and bike discs, an the rear I have Mini Drums using 0.75 single cylinders on each side.
My options are going to be a balance bar and dual cylinders, but, 0.625 cylinders (which are the smallest I can find) might be too big, Personally I think .7 is as big as I want to go with a single cylinder or find a dual circuit master cylinder to suit and make a bell crank system so I can use it,
Suggestions gentlemen please...............................................................

If you can go upwards the mini or metro cylinders are fairly compact not sure of the bore though.

If I don't use the baked bean tin M/cyl it might work The metro one, If I run it sideways via a bellcrank It might work, I need to look and see how much room there is behind the pedal box behind the accelerator pedal and to the door post.
As long as I can run pipes to the master cylinder to replace the integral bottle, oriented so it does not trap air it could work,