I read it wrong
..my bad makes sense now...
Service menu: up/down/enter on the Projector at same time.
The cable length thing is accessed through the remote, as mentioned.
Your lucky you decided to go with the Mits over the Epson 8350. The Mits DLP is a FAR FAR better picture overall. People wrongly assume because they are near the same price, that the PQ is near the same, but it isn't. Although that said, most people probably don't care about the differences in PQ I suppose, or at least I guess ignorance is bliss.
The only two LCD projectors I can stand are the Epson 8700ub and the Sanyo z4000, but even then in BRIGHT scenes it still can't quite match DLP.
You don't lose black levels with gain screens as long as you have your room treated correctly and you don't make your PJ too bright. A gain screen just changes the white levels and black levels at the same time, screens are passive devices.
I favor the High Power 2.4 gain screen for budget conscious people (heck for most people even), but if you have a white ceiling and ceiling mount the Mits, the HP screen may mess up your black levels due to too much light reflecting back to the ceiling.
The 8700UB is a different story, but that didn't fit in the budget.
While I wish I could see more owner screen shots and YouTube vids of material from the HC4000, I know they don't any projector justice.