here is my setup, factory fan clutch on the engine side, works like a charm, of course I think hottest ive ever dealt with is sitting in bumper to bumper traffic in 102 degree weather
Another thing that could help is to add more water to your antifreeze mix. water transfers heat better than antifreeze, so the higher water content the better, but at some point you start to lose corrosion protection and your boiling point will drop, so I wouldnt go past 60% water