I warped 18 yards of white 8/2 cotton so that I would have plenty for the samples and more for some towels to sell at a Christmas fair. I wove the samples up without too much problem using a fine 28/2 white cotton from Finland as the tabby weft and some Harrisville Shetland wool for the pattern weft. The wool seemed to stick in place at the selvedges without too much problem. The real problem came when I tried shifting to the towels. I used an 8/2 cotton and my selvedges were a real mess.
I called for help on the Yahoo group called WeaveTech. Sandra Rude, who is weaving on a Jacquard loom and using multiple wefts, came to the rescue. She told me how to elongate the regular basket weave selvedge treatment so that you throw two shots in each shed.
In the draft above, your threading is on shafts 1 and 2 on the right side and 4 and 3 on the left side. This configuration is important. You may use any four shafts on your warp for the selvedge treatment and I either use the first four or the last four.
To try this out on the warp I was weaving, I cut four selvedge threads on each side and rethreaded them to shafts 21, 22, 24 and 23. Then, I took my lift plans and added the eight pick treadling sequence to those shafts. You must make your liftplan picks a multiple of 8 before you add the selvedge lifplan so that it transitions correctly at the end of your treadling sequence and starts over again.
Sorry that this is so small, but I hope it is large enough for you to get a clear picture of the threading and the liftplan.
Once I resumed weaving, this is what the selvedges looked like.
It is important to remember that you thread your selvedges according to the plan given and start your weaving from the right side. The selvedge draft shown starts the treadling at the top and works down. When I actually do my drafts, I use the convention of treadling starting at the bottom and working up in the liftplan mode.
One last comment about basket weave selvedges. I use them all the time when I weave towels and I am usually using one shuttle. If you want to add basket weave selvedges to other weaving projects that only use one shuttle, use this draft. For a good description of the process, see Handloom Weaving Technology by Allen Fannin pages 264-265.