Recent communications with customers suggest the White-Strong-Flexible material is more than suitable, but does need a primer-filler (Auto-shop, 'Duplicolour') paint to smooth out the 'powdery' finish. I've had to leave holes in the tank ends to allow the liquids to escape that are used in manufacture, but I've supplied the two tank end-caps on a sprue. The king-pin fits a Con-Cor tractor unit. Frosted Detail would be best for the fine details. The wheels are now 'fixed' to prevent manufacture problems. My thanks to Prof. Bill Guegold & Martyn Read for their photos (note, tractor/cab not supplied).