After placing the regulator on the left side of the bike, I connected it directly to the battery-ground connection with a 4 mm^2 wire, so I think that the ground connection can be even better than the original (I measured 0,00 ohm resistance...)
About cooling... I see that the main plat could help thermal dissipation, but I wonder if it is more or less efficient than a better air flow... maybe the best thing is to measure the temperature difference in both cases!

LC