Well, down but not out. The card I made is apparently closing A/A1 before T&R make it. So... hold doesn't work.
I'll be getting one of sandman's devices one day. But for now, I just wired my homemade circuit to A/A1 of line 3; so if the line 3 is lit, line 1 is in use. Not perfect, but hey, I need to find a use for all the extra keyset bulbs anyway.
The saga will continue, I'm sure....
Meantime I've learned one heck of a lot about how the cards function. Thanks everyone for your comments and tips.
- Matt