I don't think I said anything about correlating degrees to ft lbs. But if you have say a 4 inch long 1/4 20 bolt and you tighten it so it is snug and then tighten it 45 degrees, you will have stretched the bolt 0.0125 inches. So for a 4 inch long bolt you would have stretched it .0031 inches per inch of length. Now assuming this is less than yield, you can loosen it and retighten it over and over. No new bolt needed. You don't worry about flexing the springs in your car, do you. Stretching less than yield means it returns to the original length when the stress is removed.
If you use a different length bolt, or a bolt with different threads per inch, you have to calculate how many degrees to tighten it for the stain you want.