the Merlin: You might need to divulge how you worked the gasket & nut inside before you frustrate those who will try this. BB includes a cut piece of plastic tubing to aide in putting in the BB valve.
Go ahead and buy the better bottle valve and plastic tubing for $45. I did this for $3. I do think everyone should try this. It's very easy. I hope to explain it clearly and concisely. You'll need Keg Lube, about 5' of finishing line, a small piece of wood like a tongue depressor or a paint stirrer, and a long, skinny rod or handle. Cut the wood to just bigger than the size of the nut. Drill a hole through the piece of wood and attach the fishing line.
Set the spigot to open and string the fishing line through the spigot, exiting out the red nozzle. You can then move the piece of wood through the other gaskets and nut. Here's what it'll look like minus the better bottle...
Apply very little keg lube to one side of one gasket. Stick this gasket onto the nut. Place the nut/gasket combo through the mouth of the better bottle and gently slide it down to the hole at the bottom. The wood piece and line should be strung through the spigot and one gasket. Now work the wood up through the better bottle hole and up through the gasket and nut on the inside. Insert the spigot threads into the better bottle. Pull on the fishing line to create force to pull the gasket down over the treads of the spigot. Once the nut comes in contact with the spigot threads, insert the rod through the mouth of the better bottle and rest it on the nut...
Now pull on the fishing line while rotating the spigot from the outside. Keep the rod on the nut so it doesn't turn. Once the inside gasket comes in contact with the better bottle, you can completely hand-tighten it without needing the rod. Now turn the better bottle upside down and loosen the fishing string to allow the wood to exit out the mouth.
It's really easier than it sounds. And the spigot can be easily removed because you can keep tension against the inner gasket as you unscrew from the outside...no rod needed for that.