40" and wooden would be a Junior PTC, I believe...not exactly adult friendly (a friend and I, both rather skinny, could barely fit in the car)! I'd have to ask a few friends that have better knowledge/connections regarding PTC products and their safety requirements, but I'm pretty sure the "regular" PTC cars carry either a 42 or 48 inch restriction. For Wooden Warrior it looks like anyone between 42-54" can be accompanied by an adult, but no clue what the Timberliner minimum restrictions are, since only two coasters use them so far.
So if it would carry a 36" restriction, that would seem to bump out a true wooden coaster. The next closest thing would be a steel coaster on wooden supports (think Gemini at Cedar Point).