Epaulettes are a bit like medals. They are normally awarded to you by somebody else and if you buy them yourself you are being a bit of an impostor. I understand your reasons for getting them though.
I can understand flying clubs giving their instructors epaulettes as they are a symbol of authority although there is something faintly amusing about seeing someone with a white shirt and 4 stripes on his shoulder walk out to a Cessna 152.
Yes 4 stripes is the norm for a Captain of an airliner though flying clubs often use less.There is no distinction between gold and platinum stripes. Gold was the tradition but platinum appeared in the 80's and gold now seems a little old fashioned in the UK though common in the middle east.
If you wear a uniform through places like Egypt and the Sudan it may well lead to other complications. For instance they may ask where is the rest of your crew and if you have a uniform they may not allow you through security unless you also have a company ID card. If they discover you are doing a private flight but are pretending to be a professional pilot and wearing a uniform you might be creating a few extra problems for yourself. I seem to remember David Cyster having problems in Egypt in his record breaking Tiger Moth flight back in the 70s. If he was a pilot where was the rest of his crew, if he was a passenger where was his boarding card etc!