Stereo & Electronics - Making Weatherpak connections, T splices?

I am going to replace some cheap connectors on my 'special lighting system (http://home.ptd.net/~chrispav/transam1main.html)' with Weatherpak connectors or something similar.
I need to make some T splices on a couple connections, that is, 2 wires soldered/crimped into 1 end of the connection. Is this possible? I see that the weatherpaks have pretty tight tolerances and need the water tight seal. Would there be a good way to make a T splice on the middle of the wire and have it be totally watertight and secure?
Anybody with experience have some ideas on this?

Yeah, just strip and tin all 3 wires, solder them toghether (two on one end, one on the other end of splice. get 2.5"-3" of heat shrink tubing, position it in place, and fill it with RTV (silicone) until it comes out of the other end. Then heat the heat shrink, and excess RTV will ooze out of both ends. Shrink the tubing as much as you can, then wipe off the excess RTV. That is a weatherproof/ watertight connection.