This forum is awesome.
Without it, I seriously doubt I would have the testicular fortitude to even think of recharging my own AC.
$28 at AutoZone later, I have cold air.
I bought one of their can tapper/guages and a can of straight R-134a, which is on sale for $8.88 right now btw.
With the AC on max with 91 deg F ambient temperature, and a 72 degree dew point, before charging I had 25 psi on the low side.
I slowly added R-134a ...around 35 psi my aux fans kicked on while idling.
I put a little bit more in until I hit 40 psi. Maybe half a 12 oz. can total, if that.
The instructions on the package said to go for 45-55 psi but I remembered people on this forum recommending 25-35 psi as normal, but I'm thinking that the heat increases the low side pressure, so I'm hoping I've hit a happy medium.
Am I close?
I haven't measured the vent output temperature, but it is now palpably cold!!
I must have a slow leak somewhere; it's taken a couple summers for my AC to go marginal.

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Bob Roe
Lehigh Valley PA USA
1973 Olds 88, 1972 MB 280SE, 1978 Datsun 280Z, 1971 Ford T-Bird, 1972 Olds 88, 1983 Nissan Sentra, 1985 Sentra, 1973 230.6, 1990 Acura Integra, 1991 Volvo 940GLE wagon, 1983 300SD, 1984 300SD, 1995 Subaru Legacy L wagon, 2002 Mountaineer, 1991 300TE wagon, 2008 Murano, 2007 R320CDI 4Matic 52K, some Hyundai, 2008 BMW 535xi wagon, all gone... currently
2007 Honda Odyssey Touring, 2014 E350 4matic