FiTech EFI system

I'm about 60% done my install. I usually take 2 or 3x longer than what they say to install something...lol But I also had to do some extra work. I removed my Holley blue pump and installed mechanical pump back on so had to change some of the main fuel line. And I had to extend the wires about 20" for the O2 sensor. Not sure if others had to do that but I found that harness way to short to run it properly and out of the way. I have FCC mounted and high pressure line from that to the throttle body and return line back to the tank all done. I had to order some new fuel line and fittings to run from mechanical pump to FCC so waiting for that to come in.
What did you guys do about the coolant sensor install location?? I am running big block and I have my mechanical temp guage in the normal spot on my aluminum water pump and have the factory stock electric sensor in the small hole in my water pump. Not sure there is any room anywhere esle on that water pump to drill for the supplied FiTech water temp sensor?? I have a plug in the front of my block just below the drivers side head that seem to go to coolant but that hole is too small for the suppled FiTech fitting and not really sure I should be drilling the hole bigger in the block!