Most of the planes that I fly are 40 size. When I converted trainers to tail draggers (Eagle 2, Arising Star H9 Cessna) I used 1/4 20 plastic bolts. Any kits or ARFs that have metal bolts suppliedget replaced with 1/4 2o bolts. (4*, H9 Cub). The other day one of my flying chums had his NEW Seagull Stearman up and on it's first flight the plane lost power. He had to put it down out in the cow patch and did so rather well but the rough ground took the landing gear off and ripped out the bottom of the fuse. He used the supplied 4 Metal bolts and blind nuts. I'm positive if he had used a 1/4 20 plastic bolt set up he would not have had the same damage. IMHO