Yeah, that would be my advice too !
Give it a go, if you feel confident.
Most of the time, you can do a MUCH better job yourself, than compared to a full time sparky, as the Auto Electrician is more concerned with finishing the job, and getting his money, rather than little fiddly bits like spending an extra hour running the cable through some hard to get to place, just so that wiring can't be seen from certain angles.
Also, If you do it yourself, if there are any further problems later on, you will have a fair idea of what went wrong, Unlike if a sparky did t for you.
I Agree with all the posts here.
Get yourself the following
1) Workshop Manual ! (Worth their weight in Gold).
Even if you cant afford one, go to a few public Libraries ! They tend to have common models there, (Falcons Commodores, Kingswoods, etc etc).
Take a photo copy of the Electrical Diagrams, take them home, and have a good look at them.
2) A large (80Watt) Soldering Iron, and heaps of Solder.
3) Lots and Lots of good quality Electrical tape. (Cheap Quality tends to lose its stickyness, on hot days, and can come apart, meaning exposed wiring can short out on the chassis, and other wiring.) The Best Electrical Tape I have found is 3m Brand. You can get 5 x 30m Rolls for around $12.
4) Take your time with the Job !
The good thing with older cars is they are relatively easy to work with, in terms of electrics. There is only the basics that need to be completed. (I.E. Ignition, Starting System, Accessories such as Radio, Cigarette lighter, Heater Fan, Wipers, Headlights, turn signals, and Hazards.)
If you treat every section, or every part as an individual project, you will find the Job so easy ! (Eg Takle the Starter and Ignition first. Spend 1 day on it, and take you time, when you get these working, move on to something else).
No Auto electrician Tackles a whole car at once ! ITs always bit by bit, slowly slowly.
If you do it yourself, then you can look at introducing some more accessories. Eg. Central door locking, Alarm, Power Windows, Interior Light delay, etc etc.
Sparkies tend to charge an arm and a leg, if you want the car back urgently. (Say for example you wanted the car re-wired within 2 weeks, from nothing).
Some will charge a lot less, if you let them do the Job in their spare time, (E.g. 2-3 Months, some sparkies will re-wire your car for about 1 grand).
Again, Its not really a difficult job
Hope this helps !