Thanks for the response, but I managed to get it installed. Here's what worked for me with a Badger 500 garbage disposal unit (GDU) and a Kohler Executive Chef sink. I used 1" ID thick wall black hose from HD. They used to sell an appropriate length (about 20"), but now they have it only in 10' lengths. In the shorter lengths, over by the garbage disposal units, they have shorter lengths of the clear, braided wall type. It might work. For the air gap (AG), I used a copper one made by Eastman, rather than the cheap plastic ones at HD.
1. First, measure the thickness of the sink + AG rubber mounting washer. Temporarily, screw the top piece onto the AG as far as you can. Theb spin the lower locking nut the measured distance down from the top piece. Remove the top piece and push it up from below, and have an assistant screw the top piece back on. Snug to the sink, but don't tighten.
2. Install the GDU in the sink. and connect main outlet to the sink drain.
3. Laying on you back under the GDU, hold the hose with one end near the GDU dishwasher 1" inlet port and the other near the 1" outlet port of the AG (the one that angles out). Twist the AG into the position where that outlet port is best aligned to minimize the required bending of the tube. Tighten the AG
4. Now, slip 3 hose clamps loosely on the pipe. Also, rub a bit of lubricant inside one end (SylGlide) and slip it onto the GDU inlet port. Tighten the clamp.
4. Put a piece of masking tape or something else you can mark on with a pen along the side of the hose over the several inches at the free end. Then hold it up to the AG outlet port and mark a cut point, allowing for an inch or so of engagement. Then cut at the mark, lubricate the inside, and shove it onto the AG. Tighten the clamp.
5. You might see flattening or kinking at the sharpest bend point. Slip the third hose clamp to that point and snug it up.
6. Connect the dishwasher hose to the AG inlet port (the one going straight down).
That's it.
Here's a photo:
http://www.efsowell.us/Photos/AirGapInstallation2.jpg
Ed S