David, Not sure what you mean by natural lighting effect. If you mean an indoor interview style lighting, 1000w lights are pretty bright. Follow the advice that Dennis gave and you should be OK.

Umbrellas are for defused light but they are uncontrollable so only use them when you want to flood an area with diffused light. You really want a softbox for something like a diffused key light because it is more controllable.

~jr

Regarding durability of Lowel - They hold up pretty well for owner/operators. Rental houses hate 'em and usually don't carry them because they get beat up pretty easiliy in rentals. As Glenn mentioned, especially the omni barndoors, but other stuff too... all lightweight stands require some care.

I'd not hesitate to buy them as an owner/operator or with a limited number of people using them.

Arrilite is a comparable open face instrument that rental agencies love because they hold up.

As mentioned above, a standard location interview kit is 4 sources: Key, fill, backlight, and background. But there are techniques to use fewer. Lots of people using softboxes on key are just using a reflector on fill, this works because the key wraps around the fill "side" quite a bit, and, without an egg crate, a soft box throws a lot of light sideways as well as straight ahead.