Inspection revealed the alloy rims I recycled from a ladies bike shop Schwinn actually had a smaller 11t high gear!
Using Sheldon Brown's gear calculator:
11 - 28t 7 speed alloy wheels original
For 26 X 1.9 / 54-559 / MTB tire with 170 mm cranks
With Shimano 11-13-15-18-21-24-28 7-speed Cassette
46 t chainring
11 t 108 gear inches
13 t 91 gear inches
15 t 79 gear inches
18 t 66 gear inches
21 t 56 gear inches
24 t 49 gear inches
28 t 42 gear inches
So this is as I built it last Winter.
The Ross steel wheel set has a 14 - 28t 6 speed:
For 26 X 1.5 / 38-559 / MTB tire with 170 mm cranks
With SunRace 14-16-18-21-24-28 6-speed Freewheel Cassette
46 t chainring
14 t 82 gear inches
16 t 72 gear inches
18 t 64 gear inches
21 t 59 gear inches
24 t 48 gear inches
28 t 41 gear inches
So after swapping out the wheelset, 6th (top) gear was about equal to 5th gear was with the alloy Schwinn wheels.
Finally, I swapped the 26x1.5 rubber on the higher geared alloy wheels:
For 26 X 1.5 / 38-559 / MTB tire with 170 mm cranks
With Shimano 11-13-15-18-21-24-28 7-speed "ac", "aj" Cassette
46 t chainring
11 t 104 gear inches
13 t 88 gear inches
15 t 76 gear inches
18 t 64 gear inches
21 t 55 gear inches
24 t 48 gear inches
28 41 gear inches
So bike will now be only slightly lower geared than before.