Why not sneak two 10" pusher fans on the front side of the radiator. Wire them to a switch. I use them for when I am in traffic. I have 3 row champion aluminum radiator. Jaguar fan clutch with vicious fan. Yes I built my own fan shroud. 450 hp 340 six pack.
You by chance have any pics of this set up? I'm thinking of adding 1- 16" electric fan to the front of my rad. Car wants to heat up sitting in traffic but if fine causing down the road. - And this has been working good for you!??