My understanding is dimming can change the spectrum on some bulbs, so it could be counter-productive.
For $200I got the Philips 315W mogul based LEC's and ballasts from
Advanced Technology, and that included shipping. I already had both horizontal and vertical hoods for my CMH's, so I just use them.
The mogul based bulbs have a bit more UVA&B. I'm getting frostier buds, and more of them, than I was from 400W CMH's, and they work really well... plus my electric use is less, and so is the heat... I'm just waiting for Philips to discontinue these, lol!
I didn't think my Bodhi stuff could get any frostier, but it has!
Now, back to your regularly scheduled programming, ha!