I made the F-805D brackets - making sure to make a left and a right. The brackets are 2" long but are sourced from the 15' angle that comes packed with the 2) 18' longerons. Based on what I have read, the fact that Van's gives you three 15' angle to make parts with is a throw back to before the RV-8 kit was prepunched and all of the smaller longerons had to be made from un-punched angle. A bit of overkill - but ok.
After the brackets were made I clecoed together the forward inboard seat ribs that have prepunched angle attached - with nutplates that were drilled/countersunk. After the seat belt brackets were clecoed onto the ribs - everything was drilled.