>>1714385Get chair/stool/whatever with an even surface. I used a little stepladder like pic related, but anything flat, firm and high enough to sit on works. Put sheet of thin but soft material on it, like cardboard. I used a thin sheet of foam I had spare of from DIY stuff. Put layer of tinfoil on top. Sit down, try to press your ass onto the tinfoil with a little pressure, bob fore and aft. Get up. Tinfoil will have two visible indents of your seat bones. Get a sharpie and mark the center points of these indents. Measure distance between center points, that's it. Alternatively, if you're from Europe, you can have SQLab send you a free measuring kit via mail which is a somewhat more elaborate version of what I described but functionally the same.
