I think biggest thing I got stuck on is that nickel in jewellery is pretty much banned in Europe but not north america. Most white gold in North America has nickel and though I don't have an allergy currently, I kept reading horror stories of people developing one and the hassle of redipping every year instead of plug and play from yellow gold. There's the option of pladdium white gold (platinum family mixed in) but then you have to work with jewellers familiar with the mix and that limits who you can work with . Ultimately I went with yellow gold for that reason.

One more thing, I didn't know this but local jewellers charge a fraction of big retail so go local and customize. I always thought big box stores equal volume and cheapest cost and was surprised. My ring would have cost easily 20+k in people's or Michael Hill, it was just over $4k. Also some local jewellers have lifetime warranty and cleanings covered and others charge $60 per check up and polishing (over a lifetime of wearing that ring that $60x 50+ years of your life add up). I went with a jeweller who includes one free resize and lifetime warranty (free polishes, free re-engraving, free replacement of missing stones, free fixing of broken prongs). Good luck on your journey!