So my dinghy
is more or less serviceable. The Leafield C7 valve for the forward tube is leaking, but after poking it and putting some astroglide on it, the tube stays reasonably turgid for a couple of days. As Kenomac said -- pumping up the dink every couple of days is not really that big a deal.
Meanwhile, I have found instructions for how to overhaul
Doesn't seem like a big deal.
I've just been spoiled, terribly spoiled by this dinghy, because I have never given a single
thought to any of these questions. I've either added or removed air twice a year with the change of seasons for all these years. Alas, the dinghy is one more thing which needs some attention once in a while.