I always seem to have an opinion on sleep issues !
1. I think an 8 month old is more than ready for controlled crying. I have read the Australian article as well as a similar one by the American Infant Mental Health...not sure I have the name right there. I think both articles fail to recognise that by doing controlled crying for a few nights, the baby actually cries LESS than a baby who wakes constantly in the night for many months or years. So, add up all the unattended crying minutes of a baby doing controlled crying vs a baby who wakes up constantly for another year or so. Controlled crying just seems the more humane option for both parents and bub. I also think at 8 months a baby needs a good nights sleep. If they wake up many times in the night they can't possibly be as well rested.
I recognise that not everyone will agree with my opinion and different people feel very strongly about this issue.
2. I think 5 weeks is too young to try controlled crying, as they baby is too young to learn what it is supposed to do. However, some babies just like a grizzle before they go to sleep, that is their settling method. I would make sure bubs is fed, dry, warm, etc, then kisses, cuddles and goodnight in a darkened room. If he starts crying, leave it for a few minutes, before going in and patting/stroking/etc. If bubs is still upset, pick him up and reassure him. When he is calm, try again. At 5 weeks, if they haven't settled in, say 40 mins or so, I'd get him up and go for a walk or something to change scenery.
The Baby Whisperer book describes this technique (pick up and put down method) better than I can. The author tells the story of the first few times taking a hundred pick ups and put downs before bub goes to sleep, but eventually they recognise the sleep cues and don't fight it so much.
Also remember that babies will cry the most in the first 6 weeks of their life, getting worse at around 6 weeks. By 3 months they will be getting better and by 6 months you'll (hopefully) have forgotten all the pain.
Just do whatever you need to do to get through those first 6 weeks. If that means leaving bubs to cry in the cot for 10 mins whilst you have a sanity break and a cup of tea, so be it.
There are some sleep and settling strategies available at the Karitane website:
http://www.swsahs.nsw.gov.au/karitane/docs/survival.asp
for relevant age groups. Karitane is a sleep school in Australia.
Good luck.