It looks viable, so will try it out this weekend when I have time.
Another suggestion was to have an array of subscripts with values  0-2,
sort of like indirect referencing.
Then can cycle through the array of subscripts using trinary counting
(each variable has 1st, 2nd and don't use)
The while thing is about 6 lines long, but don't know if it will work yet.
Again, thanks for your input ...