We use the Topeak Mt. Morph (bit shorter/lighter than the road version).
Also carry one CO2, in case pump fails (have broken/busted pumps, but never a Topeak).
Free air is hard to beat! 100 pump strokes gets us 100 lbs in 700x25 tandem rire. 120 strokes/120lbs.
No flats in 7 years? Yipes you either must not ride much or have great karma!
On a cold day CO2 discharge will not warm you . . . but 100 pump strokes will!