The hight of your knee when bent plus an inch or so for good pressure. My design was always the traditional site joiners, here in Scotland anyway. Made from whitewood flooring, whichever was available site to site, two legs knee height (mine was 27") two leg feet, a base and two side, finally a top.
1. 1 x top = 30"
2. 2 x sides = 26"
3. 1 x base = 24 1/2"
4. 2 x legs = 27"
5. 2 x leg bases
The design -
- ...pinenot