"Seems to me" that you need a "freeze proof" sillcock.
These are about 1' long (you can get 18" ones) and the idea is that the
actual valve is inside the house where it will not freeze. The sealing
surface is like most globe valves and the washers should be replaced when
the valve doesn't make a leak tight seal. It shuld also slope SLIGHTLY down
to the outside so that water completely drains.
Yes, the "shell" is quite thin but it only has to endure real pressure then
the sillcock is connect to a hose AND the hose is connected to a shut off.
These valves are quite solid from the connection to the household water up
to the actual water sealing surface.
"After installing the gate valve last year in the spring and leaving it
open, I closed it in late fall and opened the sillcock. Water dripped
out of it right from that point, so I had to close the sillcock.
Maybe some air stayed trapped between the two and helped out, but I
would much rather have a 100% sealing valve behind the sillcock."
Don't get me wrong, it's nice to have "belt and suspenders but a freeze
proof and properly maintained (good washer) sillcock should not leak.
"I had bought several of these gate valves at once to swap guts in the
future, so I had the chance to look at an unused one yesterday. I
wasn't impressed, that's when I DAGS on their design and found they
aren't known for their tight seal capability."
Well, ball valves in "household" sizes are cheaper and more reliable than
gate valves. In either case, it's best to operate them wide open are
completely shut. If you want a metering valve, globe valves do quite well.