Bill,
I have never been a fan of putting the oil cooler in front of or combining it with the radiator. First, if you use an internal heat exchanger in the rad for either oil or trans fluid,(not that you suggested this) you still only have the surface area of the rad fins to transfer the heat out of the water. Therefore unless you increase the rad size accordingly you can only remove so much heat. This is a pitfall I saw a lot in racing. Guys would swap a standard rad for one with a built in oil heat exchanger of the same core dimensions and continue to have problems. In the end, they still didn't have enough heat exchanger area to remove the heat. This all leads to my next comment. If you put the oil cooler in front of the radiator, then the heated air will now be moving through the radiator and will now not be able to remove as much heat from the cooling system. My recommendation would be to run and external cooler mounter somewhere other than in front of the radiator. The one in the Bull Run car was recommended by Wegner. We will probably look into that one as well. The fan gives you more versatility in mounting if you can't mount it somewhere you are able to get a duct to it. If the only place you have to mount it is in front of the rad, then so be it. That is not as bad as building it into the rad. You are at least adding heat exchanger area. I would not put the pusher fan on it then. If you didn't have it running all the time, all it would do is block the natural air flow from it and the radiator since it would be in front. (This is why I don't like pusher radiator fans as well)
As for pressure drop, you are going to have to give it a shot and go from there. Obviously the more elbows the more pressure drop down stream. The bigger the line the better as well. We'll be talking.
