I have three touring bikes, two use 26 inch wheels, below.

The lowest gear on my medium touring bike has 24 granny chainring and 32 big sprocket in back, which is slightly higher than you are looking at. When my heart rate gets too high on the uphills, I get off the bike and walk it up. That lowest gear is 19.3 gear inches.

The lowest gear on my heavy touring bike is 16.2 gear inches, this bike has a Rohloff hub so I had to choose what size chainring to install on the bike. This lowest gear has a cadence of 72 at a speed of exactly 3.5 mph, which is what I thought would be perfect for my slowest speed up hills. That said, some hills have been climbed on this bike with a cadence in the 60s, so roughly 3 to 3.5 mph is what I found to be the slowest speed achievable without excessive steering correction.

Using the numbers from Djb, you would have 17.1 gear inches, which is in between the lowest gear on my two 26 inch bikes, should work out nicely.