broom handle works if you also have some u joints (you gotta buy anyway). broom handle fits inside the joint like the double d shaft would if you simply buy a handle or wood dowelling that fits the joint shaft size of the u joint and then grind it down some to be shaped like double d shaft. slip it inside the yoke and gently tighten up the retainer screw to hold it there. shorten the shaft (broom handle) as required to get the lengths you need. you can figure it out pretty quick if your set up will have enough room to fit the shaft through all the stuff in the way. waaay cheaper and easier to work with because it is just wood and grinds away pretty quick.
remember the u joint has a max operating angle and should be kept away from the exhaust heat. more angle in the joint means more speed differential between the input (steering wheel) shaft and the final output (steering gear input) shaft. a shaft with 2 joints and the input and output shafts at the same but opposite angles will cancel each others speed variations out. a shaft with 3 joints will compound the issue and cause binding and faster wear of the joints. if done incorrectly the steering wheel, in one complete turn, would turn the steering gear faster or slower during certain parts of the rotation. it would be one complete turn but the steering gear would speed up and slowing down twice during one constant speed rotation of the steering wheel. maybe not what you want to happen. worse when the angles increase.
check this video link for a better explanation
https://www.youtube.com/watch?v=gmV4qwLfOMY