You said you weren't handy with a wrench. That can mean one of two things, you have no experience but you're willing to learn or you have no desire to. Not judging, some find pleasure in working on mechanical things, some would rather pursue other things. If you fall into the no desire category IMHO an old Norton won't be an enjoyable experience. The only way you might make it work is to buy a perfectly restored bike (10K+) done by someone who knew what they were doing and then have somebody close by to regularly service it and fix the odd glitch that knows what they are doing. I don't know anyone in SA, but there are some in Austin, Dallas and Houston that can work on them. At going shop rates that's going to require deep pockets and they will do it on their schedule.
You might get lucky and find someones baby at a reasonable price but in my experience your average Craigslist or Ebay bike is going to require you to spend at least a few months and a fair amount of dollars to get to reliable riding status. Then there's ongoing maintenance. Unlike modern bikes when these bikes were built it was just assumed the average owner would change the fluids, replace the tires, chain, adjust the valves, set the points, set the timing, rebuild the carbs, decoke the head and on and on. Compare one of their owners manuals to one today. They practically told you enough to rebuild the bike, today it's all about how to set the security and adjust the stereo and heated grips.
Not trying to be a downer but just trying to be realistic. If you do want to learn how to turn wrenches this board is a great resource.