>>I can still be very set on going a certain direction sometimes.
Believe me, I understand this. I have made many crazy contortions to circuitry because I wanted it to fit in a certain project box or work with a certain display or whatever.
>>Wait, why is it 1.3v? Due to the zener in the circuit?
Not the zener, just ohm's law, like I said. Rs is now 2.6Ω. At 500ma, that's 1.3V.
>>Couldn't I put a 3-4w bulb before the lm317 in parallel with the circuit to use up a few ma, therefore lowering my overall maximum charging current?
Yes, but if you run the current through Rs, it will read the same on the meter. If you bypass Rs, it will goof up the regulator. If you want a pilot light, just put it ahead of the regulator so it runs off the 18V supply, that way it won't affect anything.
>>it is important to pass the gassing voltage of a maintenance type wet cell to get a full charge.
Yes, I've hear that gas-station lore about "She ain't charged till you see the bubbles in the battery". While it's true that it will start to bubble when it's as charged as it can possibly get, I would cheerfully sacrifice that extra one or two percent of potential capacity just so it doesn't gas all the time and destroy the battery.