Hi Robert,
All of the 400watt bulbs we carry can be used in either position, except 65K 400watt Iwasaki, that one is meant for horizontal only position, but we can special order the vertical one for same price.
On the heat issue, the 400watt gets pretty hot even with the reflector, but the reflector is designed to allow heat to escape behind it, so it seems to protect wood under it no problem.
jason