It is worth noting that IRD has an excellent 6-speed freewheel for half-step gearing.
14-17-20-24-28-32
Note the 3 tooth steps at 14-17-20 and then the fours.
I am running that on my Raleigh Alyeska (1986) touring bike with a 48-44-30

...... 48 ... 44

14 92.6 84.9
17 76.2 69.9
20 64.8 59.4
24 54.0 49.5
28 46.3 42.4
32 40.5 37.1

{As a 63 year old Clydesdale .. 92.6 at 48-14 is plenty high for me on the high end.}
Living in Western Washington it is all about hills.

I also have a full-blown 24" TREK 720 (1985)
with Maxi-Car tourism 40 spoke hubs with 700C Velocity Dyads and 42-622 Marathons Supremes
Chainrings 48-44-26 and IRD 7- speed freewheel with 13-15-18-21-24-28-32

by the way those 42-622 tires are 40mm width when mounted on Dyads
which gives about 2 mm of tire clearance under the rear brake bridge.