Did some research and thinking and it turns out this bench is too short. In other words, when I sit on a bench to meditated, I like my thighs closer to a 45 degree angle from my knees, rather than the 10 to 15 degree angle that the Ikuko would have given me.

I took the measurements from the website and happened to have a bench that matched in height (but not slope, not that it really mattered); turned out to be very uncomfortable.

A chair that we have and use for my nephew turned out to be perfect, a few inches higher and not that uncomfortable. And probably less than a tenth of the cost of the Ikuko.

I'm going to buy an old bench from a thrift store somewhere and make it into what I need. After that I'm going to buy materials and make a kapok.