I use a standard floor pump for the fat tires and carry a Serfas compact pump. I have never tried pumping the tires with the hand pump. However, I will tell you with the floor pump, ~10 strokes gets you 1 to 2 psi. Since the tires are high volume and low pressure, it's honestly not too different from a high pressure, low volume tire.
I totally agree and that's why I added temps, it make an amazing difference riding in the cold... I don't have a great way to compare pressure versus speed at the same temp. But clearly, lower pressure equals more work and slower speeds. Shocking, I know
Take this for example, two rides over the same route:
-10F, 25 miles, average pace
9.4 mph with Strava Suffer Score of
134
45F, 28 miles, average pace
14.6 mph with Strava Suffer Score of
56
I know that my tires were higher pressure on the 45F ride (no snow or ice) but I don't know what the pressure was at, likely 12 psi since that's my typical 'summer' pressure. Regardless, the level of work (Suffer Score) and the average pace, people get a great idea how much more work it is to ride in the cold.