Actually, I think it is much easier to heel-toe on the track. On the street, you never really press the brake pedal which makes it hard to blip the throttle enough.
On the track, you press the brake pedal a lot harder so the pedal is about even with the gas. I usually blip the throttle too much when I downshift.
I think you would downshift in towards the middle of the braking zone. You have to scrub off some speed and lower the revs so you don't drop a gear and then mechanically overrev your engine.
2015 F34 328iX GT Glacier Silver
2011 E90 M3 Monte Carlo Blue
2004 E46 M3 Imola Red