I noticed the same problem with the # 4 being too small, so I ordered a second decal sheet from horizon hobby for about $6.00 us. Received the second decal sheet fine, but there is a wider red border around all the letters and numbers compared to the sheet included in my kit, so now I have to carefully trim half the width of the red border from all edges of the # 4 to match the other numbers! It will work fine, but was surprised to find the replacement decal sheet slightly different from the one shipped with my plane. Thanks for the confirmation on engine size for the skybolt. :-).