I'm in the process of re-furbing my cooling system right now. I've never had cooling problems but, my water pump has started howling recently.
I've run a 100% stock system including radiator (cleaned 12 years ago), rad duct, cooling fan, TRF water pump and a cheap t-stat.
I'm considering upgrading to a 6 vane water pump but not completely decided yet. I have ordered a Stant SuperStat t-stat from Summit Racing ($11 with S&H). I've compared it to the old t-stat and it is very obvious, once open, it will flow considerably more coolant into the rad. I've also realized the PO installed the stock fan backwards. It still pulls air in the right direction (installed forwards or backwards, the blades will be angled correctly) but, the curve in the blades is facing the wrong way - probably reducing effectiveness some.
I've decided not to us a restriction in the by-pass hose. Just not comfortable about possibly creating hot spots in the head.
Regarding choice of fans, these only matter at idle or at traffic. If you're running hot at speed (say 35+ mph) you're issues are definitely not with the fan.
Last, in order to max cooling efficiency of the system, I run a mixture of 38% coolant, 5% Water Wetter and 57% water (103oz, 12oz and 154oz respectively). While coolant raises the boiling temp, the water is more efficient at thermally transferring the heat out of the engine. And I change it every other year. I also jack the front end of the car and be sure to burp ALL the air from the system.
Bob