Tolerance of water pump play?

I was just curious as there are four bolts that go through the timing cover correct? Any issue with the timing cover resealing after a water pump change? I guess it couldnt come at any better of a time, winter, im looking at replacing my fixed blade with a 5 blade clutch fan and i have one intake bolt that barely seeps every once in a while. Currently i have a murray water pump, is there any advantages or disadvantages on going with a high flow?