Waytek is a seller of a VAST array of electrical goods that may interest many members of and visitors to this forum. I believe they have a minimum order amount, but their prices are great for DIY people. I really can't describe all the stuff they have, and I feel the website is (currently) well organized and easy to navigate. I sourced HELLA relays and very heavy duty duty pigtails from them for some projects. If you can't easily source electrical components locally, I suggest you at least give Waytek a look, even just to get a feel for pricing.
There is a lot of what seems like good advice at the below link, such as selecting circuit breakers, and extending the life of automotive wiring and connections. Many blogs here for learning.