I assume that both you and Ckau are still having trouble with you brakes. If not disregard this message, of course you can ignore it as well
. This topic has been eating at me and I just wanted to run something by you. The MCs that both you and Ckau are using are essentially motor cycle MCs. I've had quite a bit of experience with them and they can be a pain to work with on a good day. The main problem with them is that they do not move very much fluid when they are compressed. This can making bleeding them a chore. Since you are using disc brakes, once they are bled, there should not be any problem with braking power (unless the lines are expanding). If you were using drum brakes, where the shoes move in and out, I would think that the MC was too small. However, with disc brakes, the distance that the pads move is miniscule, so you do not have to move the pedal much to engage the brakes.
However, do to the orientation of your MC, I am not sure that you are getting all of the air out of the system. The first drawing is of how a motorcycle MC is mounted. Notice that the air bubbles naturally rise into the brake line area where they can be displaced out of the calipers by bleeding. However, since your MC is upside down, the air bubbles tend to move away from the brake line and tend to collect in the MC plunger cup where they may become trapped. Is there a way that you can dismount the MC flip it over and compress it by pushing it on the floor of the buggy.
Also, Ckau may be having the same issues because his MCs are mounted horizontally. In this case the air bubbles may be rising to the top of the MC bore and becoming trapped. In his case he might try jacking the brake line side of the car as high as possible, then try bleeding the brakes in this position.
These ideas may or may not help you, but your problem has been gnawing at me a long time.
Good luck.