Thanks to all for the comments and suggestions.
I ordered the OptiLife from Supplier #1
($75.95 with shipping, but the version without the cradle), and it arrived yesterday. I spent some time during the afternoon getting everything adjusted the way I thought it ought to be. I went to bed about midnight, keen on my first night's sleep with it. It was mostly a disaster:
You'll notice that there is a dramatic change about 2:30 am. Before then the leaks were waking me up every 20 - 30 minutes. I would adjust and try again. At one point I switched out the medium pillows for the small, and thereafter it seemed to work better. The main problem was that the chin band kept slipping off. I couldn't adjust the length of the band any way to make it stop coming off. I am not impressed with the design of the chin band. The plastic pieces that it hangs on needs to project at least several cm. further back to keep the band from coming off.
About 2:30 I gave up. Leaving the OptiLife on, I grabbed my custom chin strap and applied it over the OptiLife, just as I did before with my Wisp. Notice what happened to the leak rate after that!
There are some other problems with the OptiLife. When I wake up in the middle of the night I sometimes need a few swallows of water to allay dry mouth. This was especially true during the first part of the night before I added my custom chin strap. But it is just about impossible to take a sip of water with the OptiLife on. The plastic part that holds the pillows projects backwards and prevents you from raising the glass to your lips. You have to use a straw (try to find a straw in the middle of the night) or you have to take the mask off.
The OptiLife is also inconvenient when you go to remove it. Unlike the Wisp and most other masks I have used, there is no quick-disconnect snap. It is attached firmly to the tube that it come with. To take it off you have to pull the other end of the tube out of the 6' tube from your CPAP machine. How much more would it have cost Respironics to make a quick-disconnect clip where the tube goes into the mask? I am not impressed.
I wanted to try the OptiLife because a) I was hoping the chin band on the OptiLife would make it possible to eliminate my custom chin strap and, b) the Wisp has knobs and bumps on the sides which make it uncomfortable for a side sleeper. The OptiLife succeeds to a large extent for (a), but for (b) it is a total fail.
I'll probably give it a few more nights (keeping lots of straws handy by the bed), but it doesn't look encouraging.