Personally, I wouldn't consider doing it as a permanent adjustment (but I generally err on the side of caution). You aren't going to see a substantial increase in brightness for the potential risk. I would just go with the lamp HIGH to accomodate. I would also suggest you take some of the money you saved on the purchase and get an i1 or Spyder 3 and download AVCHD to get a handle of what's in need of adjusting. (Best investment next to my RS SPL meter!)
I was following your thread, glad things worked out! I have been struggling for, what I would consider, the decent black levels that all the reviews raved about on this unit. But since this is my first experience with front projection, I may have been expecting too much (like you coming from the CRT camp).
It wasn't until I had about 40hrs on the lamp that I acquired an i1 and did my first measurements. I'm not sure I would even been able to calibrate a moderate black level within that first week, the bulb was just uber-bright. After that, between 100~200hrs the bulb finally settled into it's current brightness in which the black levels have improved substantially.
Give it some time and get ready to tweak quite a bit....
JVC X750R, 133" DaLite HP (2.8 gain), OPPO UDP 203
Denon X4300H, DIYSoundGroup Fusion 15 L/C/R, Mirage FS V2 Surround, Mirage Omnisat V1 Surround/Atmos