Gary, I have tried freezing the bolts with dry ice. It made no difference at all. The bolts have so little mass, they warm up right away. Use BoeLube on the bolts and in the holes. It takes a really large hammer, actually a short handled sledge hammer to ram the bolts home. Be really careful to check the plans for washer placement on the bolts and nuts. Once the bolts are in they aren't coming out easily at all. Don't plan on removing the bolts unless you have an off field landing and need to pull the wings. I have seen some misalignment of the carry-through bar stock. That accounts for the difficulty of inserting the bolts all the way through. There is always some misalignment of the bulkheads riveted to the bar stock. This adds up to a really tight fit. You should have a few bullet bolts to help bring everything into better alignment. Be really careful with a flashlight and mirror to be sure the holes are really lined up. Take a close look at the weldments to be sure the holes line up with the spar carry-through holes. Have a steady handed work crew that understands what you need to do to bring the holes into alignment. Three helpers are necessary to do it right. One on the wing tip, two at the root ( leading edge and trailing edge) and one installing the bolts. It's much easier to install the wings with the fuel tanks removed. That way the root leading edge guy is right on the spar. Installing one 7/16" bolt in the top and one in the bottom will then allow you to knock the others in place. Watch it with the 1/4" bolts, they can be bent easily with one errant blow. It's best to not have any wiring or antennas in the way of the hammer swing. Tape a scrap piece of aluminum to the floor so you don't scratch the inside of the belly skins. I have a small brass hammer that I like to rest against the head of the bolts and swing the big hammer into it. As the others said, don't hammer the bolts all the way through. You will need to install washers and nuts then knock them through some more and repeat until the bolt head is seated. Regarding the wrench, I have several I've made just for that job. I have ground the open end to two wedge shaped points, that allows the wrench to wedge against the weldment on the left and right sides while you torque the bolt end. There's no room for a non modified wrench due to support tubing being in the way. Regarding torqueing from the bolt head, determine the torque necessary to rotate the bolt in the spar and nut. Add that to the bolt torque specs. Repeat for each bolt. That's my method. It hasn't failed me yet. Others may disagree or have different techniques.