A needle braring on the big end of the rod is necessary because most fliers don't want to use enough oil in the fuel...Large converted 2 strokes can get by on 10%, smaller ones need the same amount as a small glow engine...Then there will be complaints about oil on the fuselage, just like glow engine...Can't have it both ways.....
If the needle bearing was not necessary Tom at BME would not go to the trouble of pushing the crank pin out and replacing it with a harder one....