Meanwhile, I found it pretty easy to heal toe in the MX, but I was doing it on my old KA Ford Laser, so it was just a matter of getting used to pedal positioning.
I found it was quite easy to pick up after I learnt how to double clutch first, which if it hasn't been mentioned already (and I'm too lazy to do more than skim this thread

I'm guessing everyone puts their 'toe' on the brake and 'heel' on the throttle? It was a bit awkward when I tried it the other way around...