Stop it. Really. I mean it. Pick a height between your thigh and waist that seems right. You’ll adapt. Don’t worry about your back. You’ll adapt. If you are really uncertain, make it a little taller and then cut down the legs. After a decade or so, your work habits will put a magic number in your head. You’ll have built enough furniture that you will know your number. Until then, pick a number.
With the shelf secure, get a couple of friends to come help, and stand the bench on its feet. I said earlier moving the top by yourself is dangerous. Trying to lift the entire bench is foolhardy. Of course, I already said I'm stubborn, so I did it myself by rigging a simple block-and-tackle using lightweight pulleys I got at the hardware store. (Not the lightest-weight pulleys, those are meant for flag poles and have a design load of something like 40 pounds. These had a design load of 420 pounds.)
I marked the holes by putting a dowel center in the end of a long piece of 1" dowel. Run it through the holes in the base plate, and bang on its end with a mallet. Rotate it a bit and bang it again, and repeat. Odds are the dowel center won't be precisely in the center of the dowel, so you'll be making a small ring of marks. The center of the hole is, of course, the center of that ring.
While a strict figure for the bench’s weight capacity is not available, a quick browse through their other stand and bench products shows a general weight capacity well above most other brands. As such, while we cannot say for certain that this bench provides the best weight capacity, it is more than likely that it the capacity is similar to the other products in the catalog.
In each Practical Woodworking Class, the daily mix consists of intensive lecture, demonstration, and student practice lab time. Lecture periods are interactive, informative, and intensive but are also an enjoyable experience. Generally, each joinery and fabrication process is demonstrated in several ways to reach or achieve the same results. For example, processes are first demonstrated with the use of hand tools. Next, the same joint or procedure is done with simple hand held power tools (such as the router). Then, the entire process is demonstrated with stationary equipment such as the table saw, drill press, and mortiser. Students choose whichever production method works best for them and is in keeping with their plan to equip a home workshop and/or around their existing home tooling.