Sensor Loupe Recommendations
The larger, Quasar loupe makes it easy to quickly check for dust in my D600. I like that I can rest it directly against the lens mount flange to inspect. If any dust is present, I use a DustPatrol 24mm brush static charged with a large Giottos blower to swipe the sensor. Then I check again with the loupe. At 3000 images, wet cleaning is no longer required. I considered the smaller model, but for the difference in price, the Quasar is a better deal, imo.
By the way, don't forget to blow any dust off the loupe before placing it over your mirror box!