–Played with bike pumps all day. Got all but one working nicely–i.e., gauge needle goes up on the downstroke and stays there until the upstroke. Web solved one issue: When I push super hard but can’t get the handle down, it’s likely because the Presta valve is blocked shut by my poor fitting of the chuck. Could also be that the “drops to zero” problem is related to poor fitting of the chuck–though I tried different ones and  (sort of) tried to keep them straight. Will try again. I may also want to have the tubes replaced, as I’ve done a lot of pushing and pulling on the valve stems. I was going to buy a bunch of Hiro chucks but then noticed (and read) that they let a lot of air out unless you remove them really fast after opening the lever. Will practice.