From my perspective i don't think you will need this complex heatsink design, because you won't push the Jazz to the same powerlevels (up to 4KW) as he does with his big heli.
I found
this graph of a heli guy using a jazz 55 with a Neu 1910/1Y using 8s lipos. Power levels up to 2.3KW and an average amp draw of 42A. On your car i would expect your highest bursts between 1.2-2.5KW but your average amp draw will not be even close to 42A. I think it would be more in the range of 8-15A.
The only thing i did is mount the ESC upside down and removed the heatshrink where the cooling plate is (this improves heat dissipation). After a hard continouus run the cooling plate feels only warm to the touch (This is with power levels up to 1.7KW and 10s1p A123 in a 9lb 1:8 buggy geared to 67km/h (42mph)).
Very clean layout ... looking forward to read about your maiden run.