[bret a ewing]

I can see both sides of the discussion. The brakes should be used to slow down the car, not the clutch/driveline, save the driveline whenever possible. Where heel/toe can help is when your turn-in on a corner is complete (even using some trail-brake) you normally have a little time to match the revs to the next gear. Makes for a smoother transition throughout the turn, also feels pretty good when you get it Jussssst right. Anyway, JMHO. As someone said earlier, takes practice and possibly some mechanical adjustments.
I have a CSX4k - I removed the pedals from the pedal-box, here is my setup:
From left to right -- 3" distance from left foot-wall to clutch. 4 3/4" between clutch and brake. 4 1/2" from brake to right foot-wall. Throttle pedal is 1 1/8" from right foot-wall.
I gave me more room to work and now I don't have to lift my foot to transition from brake to gas, just place my heel and work the brake/gas controlls in a parallel path, also by not lifting less interference leg to steering wheel. A firm stab of the right side of the brake pad brings me to perfect blip control. Have fun with it!