The CMS does work well enough on these late sets and is sufficient to do a pretty darned good calibration. I have the 92" model and do autocalibrations with ChromaPure and a DUO. To tighten up the DUO's autocalibration a bit I usually just bring down the color dEs by adjusting the luminance on Primaries and Secondaries using the displays controls. I always do a basic grayscale first with the displays internal controls before I autocalibrate with the ChromaPure DUO Combo. As I told mfiish in the Rear Projection Forum his meter is a total unknown. Even the D3 Pro on my Mits was not very good until Tom created a specific table for rear projection DLP.
So the meter is crucial and if it is a colorimeter it needs to be either trained with a spectro or have a specific table for the display type.
The whole question of calibrating at 75% saturation is kind of an advanced concept considering the huge question mark of measuring with an LT or D2 without a spectro to profile them on the display.
I use the 75% stimulus, 100 percent saturation patterns on the DUO and it works fine. You do need to make sure you are not clipping color under 100 percent stimulus by adjusting max white appropriate. I use Spear and Munsil and the AVS clipping patterns to assure headroom.
The 92" display needs to have a decent amount of contrast dialed in to make adequate amounts of light for daytime viewing. The 73" unit being asked about here has the same lamp and pretty much the same optic engine so you can easily get plenty of brightness while using a modest constrast number which tends to keep the set linear.
Mits WD-92840 92" DLP - Lumagen Radiance XS, Martin Logan Motion 40s, Ascend Sierra 2s
Older 58" Panny Plasma -DVDO DUO, JBL Studio 530
Pioneer AJs, PSB Images, Usher S520, JBL HLS-610, Definitive SM45, MusicHall Marimba