Timing Cover Gaskets

The cam in my 360 is installed 4-5 degrees retarded. This weekend I hope to advance the cam several degrees. I plan to use this gasket set for the repair work:

1973 PLYMOUTH CUDA Fel-Pro TCS45284 Fel-Pro Timing Cover Gaskets | Summit Racing

Are there any tricks to getting a good, leak proof job? I'm especially wondering about the oil pan area. I believe there are 2 oil pan bolts that must come out, but the oil pan can stay in place, correct?

I'm hoping to leave the radiator in the car, but I suppose it could come out if it made the job easier. Any tips are appreciated.
You shouldn't have to remove the radiator to pull the timing cover. To pull the cam, yes.