How should i mount my 70w hps

is an hps bulb more efficiant mounted vertical or horizontal.also any ideas on what to mount my remote ballast on.this is a modified light from hd im sure youve all seen one.thanks in advance for any help.

Well...a good HPS reflects most light out to the sides...Like the one in your avatar picture...It's long coil emits light out the sides, so mounting it vertically without a reflector is bad...even with a reflector, vertical is less efficient than horizontal. Id go horizontal with a decent reflector..

A remote ballast for a 70w? Just mount it on the wall, ceiling, or just sit it on a horizontal surface (dry, out of the way, and with good airflow/cooling)

k thanks man.looking at the bulb i see what you mean about light coming of the sides.thanks for the advice.