Sounds like your having fun!! I went thru the same problem, and decided to have a heavy duty truck spring and axle shop take care of mine. Well worth it!! I gave them my axle and I also had them install the new king pins and shim them properly and then I re-installed everything. I read here that if the axle is still in the truck you could lift the truck up using a pipe and raise the truck by placing the pipe under the king pin and the weight of the truck would drive it out, but it sounds like you already have the axle out, and so did I at the time.
Heavy duty truck shops who do spring and axle work do these king pin jobs all of the time. When I went in there he already had like 6 or 7 larger versions of what we have on our trucks in process. It kinda made me feel good to see that going on. Good luck and show us some pics if you can!!
