Zup dude. Not a problem.

I've done many tail conversions, and I can tell you that thy're alot of fun to do. Good choice in tails BTW. First of all, I have to ask...are you flush mounting the tails in with the body, or do you want them to stick out some?
Any time you do any kind of conversion, it's important to make some kind of template of what the lights are going in. So in your car, you want to take some real thin sheet metal, put the lights on top of it, and outline them. Then, hold the template up to your car to get a general idea of how much cutting has to be done. Take an oil marker and outline on the car where what needs to be cut out, and start by doing things that way. Once you have the general shape all cut out from the body, you can then start by taking that template you made, and tap welding it in place. You also have to remember that you're gonna have to bend the body lines to flow into the template that tap welded in, otherwise it won't look right when the project is 100% finished.
Remember to take alot of measurements, and to leave a good 2 inches behind the lights open for the wiring and general breathing room. Now, if you want the lights to stick out from the body a little, it's a bit easier than flush mounting. In this case, all you have to do is make some kind of box shaped template that covers the area where your stock tails are, but has a hole cut out that will fit the new tails in. There isn't kind of cutting or bending of the body when you do things that way. It just entails some tap welding, and basic body work, and you're good to go.
I know this all sounds kind of confusing, so what I'll do is see if I can make some kind of diagram in photoshop or whatever to show you what I mean. Also, email me if you want (josh@teamsr.org) and give me your number. I'll give you a call and walk you through it if you want. Good luck, give me a holler if you need anything, and have fun.... 8D