I'm going to say "where ever its comfortable". One advantage of building things yourself, is you get to make it a car you love to drive.
http://www.ididitinc.com/tech_instructions/tech_column_measure.html from their site..."As silly as it may sound, we have found that using an aluminum pie tin and a length of wooden dowel is an excellent way to determine column position and length. Use about 4 feet of dowel. Add between 1 1/2” and 3” beyond the firewall/floor if using a steering box. If you are using a rack, you can go as far as 5” into the engine compartment. Watch for clearance."
I sit in the drivers chair and lower your eyes or tilt your head down a little and you should be looking directly down the colum. Jump in a few daily drive cars and compare.. cheers Bryan
I installed mine at 40* with the intermediate shaft at 20*, splitting the working abgle on the two u-joints. I measured my daily late model at 50*. I've tried to replicate that seating position in my hotrod, but there are limits. What ever you do, it will be second nature once you get it out and drive enough.
I like it with the column pointing at my upper chest/neck elbows slightly bent, a bit more reach to the top than the bottom of the wheel hands resting comfortably at just above center of wheel column angle is relative to angle of spine and neck at comfortable seating. "ergonomics" as stated above
With the vehicle at proper at***ude and seat properly installed, sit in seat in driving position. Attach string to floorboard where column will come through and hold the other end of the string with your teeth. That's the angle to use. Have your buddy put an angle finder on the string.
I would suggest that you build/ lay out your steering column angle and seat position and height at the same time.
I read a long time ago that the steering shaft should be pointed at and to intersect with an imaginary line as if there were a straight axle connecting the front wheels. Something about giving the driver the right "feel". Just something I read and I try to do it. I think most new cars are designed that way. Anyone else have any input on this?